Part 22 in the Knox/Sollecito case
In the previous entry I invited my readers to examine the claims that Edda Mellas made eighteen false claims, a view that was advanced at the site True Justice for Meredith by an anonymous individual calling herself “The Machine.” The following condensation is my synthesis of many of those comments. Thanks to Bob, Bruce Fisher, Kate, Mary H, Rose Montague, and all of the other contributors.
False claim 1: “The prosecution had changed the motive four times during the trial. and at the end they finally had to say we don’t have a motive but it doesn’t matter.” (minute 4.22 above)
Barbie Nadeau pointed out that the prosecutors had changed their theory, but only rather slightly:
“The prosecution lawyers began their case in January 2009 by arguing that Kercher was killed during a sex game gone awry. When it came time for closing arguments, they had changed the theory slightly, trying to make the case that Knox resented her prissy British roommate and killed her in hatred” A sex attack was still involved.
Prosecutor Mignini also suggested that a hards (sic) drug like cocaine might have been involved, and certainly never said that they didn’t have a motive. Co-Prosecutor Manuela Comodi said that she didn’t know precisely what the motive was, but certainly never claimed that there was none.
Response
It is misleading to begin the clock at January 2009. The motive progression was: **Beginning motive (Nov. 2007) – Conspired satanic group sex activity.
**Beginning of trial – Conspired group sex activity.
**End of trial per Mignini– Knox’s resentment of her prissy British roommate--i.e., Knox’s hatred of Meredith.
**End of trial per Comodi – No motive but it doesn’t matter.
**Motivation report – Lust and marijuana induced aggression.
Finally, Ms. Nadeau herself reported (Angel Face, p. 158) that Mignini wanted to reintroduce the Satanic ritual, but Comodi blocked this.
False claim 2: “He (Rudy Guede) all of a sudden had money that he didn’t have earlier in the day” (minute 3.22 above)
Edda Mellas is plucking “facts” out thin air with this claim. No evidence was presented at any court hearing that showed that Rudy Guede suddenly had money that he didn’t have earlier in the day on 1 November 2007.
Response
No one knows for sure whether Rudy Guede was able to buy a train ticket to Germany or simply avoided paying. However, he had not worked in two months. The facts that Meredith’s rent money was missing, his DNA was found on the zip of her purse point toward him as the thief. By contrast, neither Amanda nor Raffaele had money problems, despite the latter having a low bank account.
False claim 3: “There is no murder weapon.” (minute 4.32 above)
Judge Massei indicates in the sentencing report that Amanda Knox’s judges concluded that the double DNA knife, the larger of the two indicated by Meredith’s autopsy, is indeed the murder weapon.
It is totally compatible with the deep puncture wound in Meredith’s neck, and according to a number of independent forensic experts, it contained Meredith’s DNA on the blade..
Response
Besides the problems with the DNA on the knife (see Response 13), it neither matched two of the three major wounds nor the bloody outline of a knife on the bed. If this were the murder weapon, it would have had blood on the handle, which would need to be cleaned off. This would remove the putative murderer’s fingerprints at the same time. The forensic police did not disassemble the knife to look for blood, as General Garofano pointed out in the book Darkness Descending. Why not? Perhaps even they doubt that Raffaele’s ordinary kitchen knife is a credible murder weapon.
False claim 4: “The Italian Supreme Court found the interrogation illegal” (minute 7.54 above)
Though this claim has been repeated in different ways, the Italian Supreme Court has NEVER ruled that Amanda Knox’s interrogation either as a witness or a suspect was illegal. In the suspect interview, she had both a lawyer and interpreter present.
Response
The Machine is being cagey with respect to what constituted the suspect interview. The Supreme Court ruled that any information resulting from the interrogation was inadmissible in the Knox/Sollecito trial, but, in a mockery of justice and a violation of basic human rights, interrogation information was entered into the trial due to the Lumumba defamation/slander case.
False claim 5: “They admit to the fact they really have no physical evidence” (minute 7.54 above)
As it took the prosecutors four or five months to present it, they have never admitted that they have no physical evidence. The stop-start-stop nature of the defense phase of the trial showed how very telling the evidence was.
Response
If the prosecution had solid physical evidence they would not be trampling all over Amanda’s rights by withholding evidence and lying as per the following:
*The prosecution withheld crucial testing information from the defense for the first 6 months of the trial of first instance.
*The prosecution lied for the first 6 months of the trial when they continually repeated that the footprints revealed by luminol were not tested for blood—documents released to the defense by the judge’s order show that the footprints were tested and that the results were negative, i.e., no blood.
*The prosecution is still withholding crucial testing information--the electronic data files (.fsa files), the instrument log files, and (if they exist) the contamination log files.
A succinct description of the lack of evidence for the prosecutor’s case is found here.
False claim 6: “They believe Meredith was killed at about 9.30pm” on Larry King Live (minute 0.54 here)
The prosecutors didn’t claim this at the trial. According to Mignini’s timeline, which he used when presenting his scenario for what happened to the judges and jury at trial, Meredith was killed at about 11.50pm.
Response
The Machine ignores the fact that Public Minister Mignini moved the time of death back an hour during his closing statement. There are several reasons for rejecting Mignini’s revised time of death, not the least of which are the contents of Meredith’s stomach.
However, the cell phone evidence is perhaps the most exculpatory. The cell phone evidence is very clear and Raffaele’s appeal makes a very good argument that it is a good indication of a time of death between
9 and 10 pm.
At 8:56 pm there is an attempt to call Meredith’s parents that does not go through. There is no further attempt despite the fact that her normal habits as shown by her phone records has her calling them before she went to bed on a regular basis.
Just a few minutes before 10 pm there is an attempt to call voicemail that is ended before the message was heard and at 10 pm there is an attempt made to call her bank that does not use the international code prefix and does not go through.
At 10:13 the cell phone shows there is a GRPS (mms) reception to the cell phone from a tower that does cover Meredith’s place but not as strongly as the tower that normally covers her flat. This is the first time she has gotten a call covered by this particular mast. The next incoming call at 10 past midnight shows the location of the phones in the garden where they were found based on the mast that covers that area.
The Massei report speculates that Meredith was just playing around with her phone at the times all these earlier calls. The defense had the idea of testing an area between Meredith’s apartment and the garden where they were found and discovered that this particular mast (the one showing the 10:13 call) covers an area between Meredith’s flat and the garden where they were found, meaning that at 10:13 the phone was in route to the garden and Meredith was already dead.
False claim 7: Amanda Knox didn’t know Rudy Guede (minute 1.02 here)
Unbelievably, Edda Mellas claimed that Amanda Knox didn’t know Rudy Guede despite the fact that Amanda Knox testified IN COURT that she had met Rudy Guede on several occasions.
Here’s the actual court transcript:
Carlo Pacelli (CP), Patrick Lumumba’s lawyer: In what circumstances did you meet him (Rudy)?
Amanda Knox (AK): I was in the center, near the church. It was during an evening when I met the guys that lived underneath in the apartment underneath us, and while I was mingling with them, they introduced me to Rudy.
CP: So it was on the occasion of a party at the house of the neighbors downstairs?
AK: Yes. What we did is, they introduced me to him downtown just to say “This is Rudy, this is Amanda”, and then I spent most of my time with Meredith, but we all went back to the house together.
CP: Did you also know him, or at least see him, in the pub “Le Chic”, Rudy?
AK: I think I saw him there once.
CP: Listen, this party at the neighbors, it took place in the second half of October? What period, end of October? 2007?
AK: I think it was more in the middle of October.
Response
“To meet” is to be introduced or come together at a particular time and place.
“To know” in this case would be “to be acquainted or familiar with.” in other words she didn’t know Guede personally. She knew who he was but didn’t know him.
Apparently The Machine must havea hard time understanding American English. Amanda met the guy 1 time and might have saw him at a club 1 time. That does not mean she knows him. The Machine is pretending that the there is no difference between the two.
False claim 8: Rudy Guede’s DNA was in Meredith’s purse (minute 3.16 here
Edda Mellas’s claim that Rudy Guede’s DNA was in Meredith’s purse is completely untrue. According to the Micheli report, which was made available to the public in January 2008, Guede’s DNA was found on the zip of Meredith’s purse and not inside it.
Response
The Machine is making a distinction without a difference. Rudy Guede’s DNA was found on her purse, on the sleeve of her sweatshirt and in her body. The lack of Amanda’s or Raffaele’s DNA on Meredith’s body is a problem for the prosecution’s case.
False claim 9: “Even the Italian Supreme Court ruled that her rights were repeatedly violated.” (minute 5:32 here)
The Italian Supreme Court has NEVER ruled that Amanda Knox’s rights were repeatedly violated. Not even her own lawyers claimed that, and no complaint was ever lodged.
The first of Knox’s two written statements couldn’t be used against her simply because she wasn’t represented by a lawyer when she made it – and she volunteered that statement, in a seeming state of panic, when she was told Sollecito was no longer supporting her alibi..
We continue next with Edda Mellas making claims in an interview for the CBS Early Show.
Whilen Edda Mellas was in Perugia, she was interviewed by CBS’s Chris Wragge. (Embedding of this CBS video YouTube on sites like TJMK is disabled, which suggests that CBS might be worried that the claims made were wrong and they should have been challenged on-air.)
Response
An even higher court is beginning to realize that Amanda’s rights were repeatedly violated—society, which demands fundamental justice and the rule of law:
*Denial of legal representation
*Interrogation statements ruled to be inadmissible by the Supreme Court were thrust into the trial due to the Lumumba defamation/slander case.
*The prosecution withheld crucial testing information from the defense for the first 6 months of the trial of first instance.
*The prosecution lied for the first 6 months of the trial when they continually repeated that the footprints revealed by luminol were not tested for blood—documents released to the defense by a judge’s order revealed that the footprints were tested and that the results were negative, i.e., no blood.
*The prosecution is still withholding crucial testing information--the electronic data files (.fsa files), the instrument log files, and (if they exist) the contamination log files.
*Amanda Knox has been charged with slander for defending herself in court.
False claim 10: The double DNA knife is incompatible with the wounds on Meredith’s body. (minute 0.16 above)
In the interview Edda Mellas made the following claim: “The knife they think is the murder weapon is way too big and demonstrated how it had to have been a much smaller knife that caused all the wounds.”
Edda Mellas’s claim above is simply not true.
Barbie Nadeau reported directly from the courtroom in Perugia that multiple witnesses for the defence, including Dr. Carlo Torre, conceded that the double DNA knife was compatible with the deep puncture wound in Meredith’s neck.
“According to multiple witnesses for the defense, the knife is compatible with at least one of the three wounds on Kercher’s neck, but it was likely too large for the other two.” (Barbie Nadeau, Newsweek).
“He (Dr. Carlo Torre) conceded that a third larger wound could have been made with the knife, but said it was more likely it was made by twisting a smaller knife.” (Barbie Nadeau, The Daily Beast).
Judge Massei categorically states in the judges’ sentencing report that the double DNA knife was compatible with the large wound on Meredith’s neck.
Response
The problems with the knife as evidence are discussed in Responses 3 and 13, however it is worth repeating that any knife could have made the larger wound, including the one that made the other two wounds on Meredith’s neck. What makes no sense is why Amanda and Raffaele would take a knife from his apartment even if their intent were to scare Meredith that night. There were knives at the girls’ flat. The notion that Amanda carried the large kitchen knife for protection (in a cloth bag, no less) is absurd.
False claim 11: Meredith’s room was so tiny, there wasn’t enough room for four people in some kind of tussle. (minute 0.27 above)
In the same interview with Chris Wragge, Edda Mellas asserts that there couldn’t have been an attack on Meredith involving three assailants.
“The space available this crime happened is so tiny you can’t have had four people in that room in some kind of tussle.”
The Violent Crimes Unit itself used detailed images at the trial (this is one below) to show that there was more than enough room for an attack involving three attackers.
Response
Edda may have been questioning whether a struggle involving four people would create more damage in the room than was observed. If three people attacked Meredith, where are Knox’s or Sollecito’s shoeprints or fingerprints? If they restrained her and throttled her, why is there no DNA evidence of this contact?
Update 15 September 2010
It was originally Raffaele Sollecito’s expert witness, Francesco Introna, who argued that the room was too small for three people to assault Meredith Kercher.
False claim 12: There is no evidence of Amanda Knox at the actual crime scene. (minute 2.06 above)
“I fact at the actual crime scene there is no physical evidence of Amanda; not a hair, not a fingerprint, not a nothing.”
The crime scene involves the whole cottage and it isn’t limited to Meredith’s room. Knox and Sollecito were both CONVICTED of staging the break-in and tampering with the crime scene.
Furthermore, there is plenty of evidence actually placing Amanda Knox in Meredith’s room on the night of the murder: the double DNA knife, and the blood she tracked into the bathroom, the hallway, Filomena’s room, and her own room.
According to two imprint experts, there was a woman’s bloody shoeprint on the pillow under Meredith’s body which matched Knox’s foot size.
Even Sollecito’s forensic consultant, Professor Vinci, claimed that he had found Amanda Knox’s DNA on Meredith’s bra.
Response
Because the date at which DNA arrived on an object cannot be known and because Amanda used the knife when she cooked at Raffaele’s flat, the presence of Amanda Knox’s DNA on the handle is strictly meaningless.
Every single shoe print found in the murder room belongs to Rudy Guede. The two imprint experts that The Machine is referring to were proven wrong. The Machine and everyone else at TJMK and PMF are well aware that this information has been refuted but they continue to spread this lie. Raffaele Sollecito’s forensics expert Francesco Vinci showed in great detail, in court, that all of the prints found in the murder room belonged to Rudy Guede.
The prosecution had originally stated that there was one shoe print matching Raffaele Sollecito’s shoes found on the tile floor. They also stated that one shoe print of a woman’s size 37 shoe was found on a pillow case. The shoe print said to be a woman’s shoe was attributed to Amanda.
The truth is, all of the shoe prints match Rudy’s Nike Outbreak 2 shoes.
The Machine’s reasoning with respect to staging the break-in and tampering with the crime scene assumes Knox’s and Sollecito’s guilt, which are the very questions under dispute. In addition, luminol is a presumptive test for blood, no more. The luminol-positive footprints were negative by the TMB test and did not have Meredith’s DNA; therefore, there is no reason to believe that they originated from blood.
If one claimed that the DNA on the bra clasp is conclusive evidence of guilt, one would have to begin searching for the three unidentified individuals also deposited DNA on the clasp. One thing that the bra clasp implies is that contamination might be alive and well in the Rome testing laboratory. Either that or secondary transfer could explain all of the DNA on the clasp.
False claim 13: “The DNA is so insignificant. It’s this tiny spot. It’s not blood.” (minute 2.16 above)
Three independent DNA experts - Dr. Patrizia Stefanoni, Dr. Renato Biondo, and Professor Francesca Torricelli – confirmed that Meredith’s DNA was definitely on the blade of the double DNA.
The DNA charts themselves show a clear and unmistakable match. Edda Mellas doesn’t seem to understand that DNA evidence almost always involves only microscopic traces of DNA.
Dr. Stefanoni testified at the trial that the DNA on the blade could indeed have come from Meredith’s blood.
We continue next with Edda Mellas in an Interview with Linda Byron on Seattle TV station King 5.
Response
The Machine ignores that Meredith’s DNA was in the low copy number (LCN) range, demonstrating that she understands less about DNA profiling than Edda Mellas does. First, LCN samples should be tested at least twice, and only those alleles that show up in both runs are should be counted. Second, Stefanoni did not use standard LCN conditions in other ways, such as the number of cycles of the amplification step and working under lighting and air-handling conditions that minimize the possibility of DNA contamination. New methods are typically vetted in peer-reviewed journals before they are accepted. Third, the Machine also ignores the well known possibility of contamination, as well as the fact that contamination is a greater risk for samples in the LCN range.
There are some problems with The Machine’s assertion that there is a “clear and unmistakable match.” First, in locus D3S1358 there are two peaks, each with peak height of about 20 RFU, which are not seen in Meredith’s reference profile. They have 15 and 16 repeats, respectively, but Meredith’s profile has peaks at 14 and 18 repeats. Second, in the D21S11 locus, the knife profile has a peak at 30 repeats, but Meredith’s profile has peaks at 30 and 33.2 repeats. It is possible to explain the two extra and one missing peak as a consequence of the amount of DNA being in the LCN range. Yet, this explanation only underscores the fact that Stefanoni should have used the services of a lab that has proper facilities and experience, instead of making up her own inferior method.
It is now well known that Stefanoni went ahead with the analysis, despite the fact that her instrument read “too low,” meaning that there was not enough DNA to continue. What is less well appreciated is the fact that Stefanoni treated this sample differently from other samples, where she discontinued the analysis under similar circumstances. The Machine ignores Stefanoni’s apparent inconsistency.
Dr. Stefanoni’s assertion that the DNA could have come from Meredith’s blood is extremely dubious. The knife tested negative for blood with tetramethylbenzidine (TMB), and Dr. Elizabeth Johnson and Professor Gregory Hampikian indicated that the test for blood is more sensitive than the test for DNA. In other words, if a bloody knife were cleaned of all traces of blood, all traces of DNA would also be removed. They and the cosigners of an open letter on the DNA evidence in this case publish regularly in the field of DNA forensics. The same cannot be said of Dr. Stefanoni.
Furthermore, The Machine ignores the fact that Stefanoni did not turn over the electronic data files or the machine logs. This failure to abide by the international standards of discovery of DNA evidence means that any claim about the quality of the results is suspect. The defense expert witnesses did not have all of the information that they would need to evaluate Stefanoni’s dubious results.
False claim 14: Amanda Knox and Raffaele Sollecito maintained the same story (minute 3.17)
Edda Mellas claimed in this interview with Linda Byron that Amanda Knox had maintained the same story for over a year when she was asked whether her daughter had lied. In another interview with Linda Byron in November 2009, Edda Mellas bizarrely claimed that Amanda Knox hadn’t changed her story. KING 5 Investigator Linda Byron asked her: “Did she change her story?”
Edda Mellas responded: “No, no. For this whole year they have maintained the story – what they did that night. They stayed at Raffaele’s, they made dinner, they watched a movie. That’s it, that’s the story.”
Edda Mellas’s statement that Amanda Knox didn’t change her story and that she and Sollecito maintained the same story is yet another incorrect and misleading claim. Knox and Sollecito both gave three different alibis. The posts on their alibis are linked-to up at the top here. Knox gave at least three different times for when she and Sollecito had dinner on the night of the murder.
Knox gave different reasons for writing her handwritten confession, and she gave different accounts of seeing the blood in the bathroom which contradict each other.
And most devastating of all, Sollecito stopped providing Knox with an alibi on 5 November 2007. Sollecito is STILL nearly three years later refusing to corroborate her alibi. He clearly hasn’t maintained that Knox was with him at his apartment – actually he claimed that she went out for four hours.
Response
Amanda has had two basic accounts; before and after the night of 5-6 November, she said that she was with Raffaele. Only on the night of the interrogation did she say anything different, and she almost immediately backed away from what she said that night. Amanda’s own words and actions and the observations of others all indicate that Amanda was physically and emotionally worn out by the time of her interrogation. We will never know how her interrogation progressed, because the police either lost it or never made a recording of it.
The claim that Raffaele stopped providing an alibi for Amanda after 1 November 2007 is among The Machine’s most serious misstatements. The accounts in Murder in Italy and Darkness Descending both indicate that Raffaele backed Amanda up, although Ms. Dempsey indicates that Raffaele got some of the times wrong. Raffaele has always stated that to the best of his knowledge Amanda spent the entire night with him on 1 November 2007. He does add that it would have been possible for Amanda to have sneaked out for maybe an hour without his knowledge.
Raffaele’s lawyers appeared before the Supreme Court in the spring of 2008 to argue for his release, inasmuch as he had not even been formally charged at this point. Their words are sometimes taken as evidence that he was claiming he was not with her on the night of 5 November. His lawyers used words that were translated as “erroneous assumption” at Perugia-Shock that they were together, but a better translation is undeserved or unwarranted assumption. The key to understanding his lawyers’ argument is that they did not call it an erroneous belief, which would be a denial that they were together. The lawyers are saying that any evidence that would place Amanda outside Raffaele’s flat ought not be counted as evidence that Raffaele were outside his flat. As Kate wrote, “She’s not saying they were together or that they weren’t together; she’s challenging the Court to provide the evidence it NEEDS to provide if it’s going to transfer evidence to Sollecito on the basis of an unsupported assumption.”
False claim 15: Amanda Knox wasn’t provided with an interpreter (minute 2.37)
Edda Mellas made this false claim, which has been widely propagated by Knox groupies, in an interview with Linda Byron on King5. It’s not difficult to prove that this claim is completely false. Knox’s interpreter on 5 November 2007, Anna Donninio, even testified at the trial. And Amanda Knox herself spoke about her interpreter when she gave testimony at the trial.
We continue next with the claims of Edda Mellas on ABC TV.
Response
The interpreter in this case was a participant in the interrogation process. According to Andrea Vogt, “But Knox said her interpreter's ‘traumatization’ was actually used to pressure her. ‘Ms. Donnino then later suggested that ... perhaps I didn't remember well because I had been traumatized, and so I should try to remember something else.’”
John Hooper reported on Ms. Donnio’s testimony: “Under cross-examination she described her role as that of a ‘mediator’ rather than a mere translator of words.”
Knox Clashes With Interpreter."
That seems to be an unusual role for an interpreter. One wonders whether there is a defined role that an interpreter can play and if there are limits to what role they can take, as proscribed in Italian law.
False claim 16: “Amanda Knox is incredibly honest” (minute 11.25)
In an interview with ABC’s Elizabeth Vargas (ABC have rendered this video not embeddable) Edda Mellas claimed that her daughter is “incredibly honest”. And Edda Mellas told The Guardian’s Simon Hattenstone that “Amanda doesn’t know how to lie.”
In fact, Amanda Knox’s mobile phone records, data recovered from Sollecito’s computer, and corroborative testimony of numerous witnesses, provide irrefutable proof that Amanda Knox has lied – again and again. For example, her lies about him directly led to Diya Lumumba, an innocent man, spending two weeks in prison – even though as recorded in prison she told her mother Edda Mellas that her claims were not true.
Response
The Machine provides no specifics for her claims. Blaming Ms. Knox for what she said during an interrogation without knowing what went on between 11 PM and 5:45 AM the next morning is jumping to conclusions without facts. The authorities knew that Ms. Knox had already backed away from her statements about Lumumba long before she spoke to her mother. And the fact that this interview was recorded means that ILE knew exactly how Ms. Knox perceived her false statement. If they had decided her statement were false on the basis of what she said to her mother, they could have released Mr. Lumumba. Moreover, the authorities were not proactive with respect to an exculpatory witness for Mr. Lumumba; he came to Perugia on his own initiative.
Amanda’s family and all of her friends have always said that Amanda is ‘honest to a fault’. Why would anyone wish to accuse Amanda’s family and all of her friends of being liars?
False claim 17: Amanda Knox could have left Italy, but she chose to stay and help the police.
In an earlier interview with Larry King in October 2009, Edda Mellas told him that Amanda Knox could have left Italy, but she chose to stay and help the police: “After the murder, Mellas said, friends and family told Knox to leave Italy—to either come home or stay with relatives in Germany—but Knox refused because she wanted to help find the killer and prove that she had nothing to do with it.”
“Many people asked her to leave, but she said no. ‘I’m going to stay. I’m going to try and help. I’m going to try and finish school,’ ” Mellas said.” Edda Mellas’s claim is flatly contradicted by Amanda Knox herself, in the e-mail she wrote to her friends in Seattle on 4 November 2007: “I then bought some underwear because as it turns out I wont be able to leave italy for a while as well as enter my house”
And along with one of Meredith’s friends who walked home with Meredith on the night, the police told Amanda Knox pretty promptly that as her status was (then) a primary witness, she was not to go anywhere. The fact that Knox did stay was of little help to the investigation – in fact, she seemed to work hard to derail it – and one of her main concerns at the time, a pretty callous one, was whether she would be staying or moving out of the house and getting a rent refund.
Response
The following statement from Judge Matteini indicates that Amanda was free to leave Italy and didn’t:
"Your family lives in the United States, so it would be extremely easy for you to leave the country," Matteini wrote. "The fact that you did not do so before you were arrested is totally irrelevant. We must remind you that your arrest was made very early, and was affected purposely before the arrival of your mother in order to avoid just such a possibility."
False claim 18: Amanda Knox and Raffaele Sollecito were not under the influence of drugs on the night of the murder (BBC Radio)
In an interview with BBC Radio after the verdict, Edda Mellas apparently stated that Amanda Knox and Raffaele Sollecito were not under the influence of drugs on the night of the murder.
This is despite the fact that both Knox and Sollecito had both themselves actually claimed they had smoked cannabis. The prosecution believed they might have been on a hard drug like cocaine, which also seems the general belief around Perugia.
Response
The Machine is engaging in rumor-mongering. There was no evidence presented at the trial about cocaine or any other drug. Amanda never used cocaine in her life. Knox and Sollecito have stated that they had smoked cannabis. One suspects that Amanda’s parents were implying that they (Amanda and Raffaele) were not under the influence of ‘hard’ drugs as opposed to mildly euphoriant-like cannabis which does not induce aggressive behavior.
Part 3. And Some Conclusions
The fact that Edda Mellas has been able to propagate so many wrong claims in the media for so long without being challenged seems to speaks volumes about the naivety and unprofessionalism of her interviewers, and of the media organisations they work for. As they usually do, ABC News, CBS News, CNN, King 5, and other media outlets should have interviewed objective crime-case professionals, who don’t have a vested interest in the case.
Instead they have relied again and again on Amanda Knox’s mother and other family members as primary sources.
Amanda Knox is not an innocent political prisoner who was railroaded in some Third World country for some very murky reason. She was unanimously convicted after a lengthy trial at which the evidence was absolutely overwhelming.
As the Christian Longo and Scott Peterson cases that we posted on below go to prove, seemingly quite normal people commit horrific murders. Probably the vast majority of murders are committed by people who to many seemed normal.
It seems downright perverse that some of the journalists who have interviewed Edda Mellas treat Amanda Knox as a victim, and with cloying sympathy ask “How is Amanda doing?” They wouldn’t dream of asking Charles Manson’s mum how the Manson girls are doing.
It is time for the sake of the truth, the legitimacy of the verdict, the relations between the US and Italy, and the peace of mind of Meredith’s family and friends, that from now on they hold Edda Mellas’s feet to the fire..
Response
The premise of The Machine’s article is flawed. The Machine presented no evidence that the press has ever relied heavily on Edda Mellas as a primary source of information. Have they actually relied on family members as “primary sources?” Or are the interviews with Amanda’s parents intended to focus on the subjective, human-interest aspects of the story? The comparison to Charles Manson and the references to cocaine use (again without providing any evidence to support this claim) make it clear that The Machine has no business complaining about another person's lack of impartiality. Moreover, Ms. Knox’s lawyers made many of the same arguments as Edda Mellas; therefore, there is no reason to single her out. The Machine has chosen to personalize the debate for no good reason.
Many of the Non-errors that The Machine cites are repeated in the defense appeals and should not be taken as errors simply because it doesn't fit with the prosecution’s case or the Massei report. Many of these issues are disputed for good reason. The Machine’s credibility for posting accurate and objective information has to be evaluated in light of her many errors in this article and others. Moreover, since the posting of the previous entry, The Machine has neither explained why the arguments are incorrect, nor made any alterations in or retractions to her essay, further damaging her credibility.
Sunday, August 22, 2010
Tuesday, August 3, 2010
Eighteen claims about Edda Mellas’s interviews
Part 21 in the Knox/Sollecito case
At True Justice for Meredith, The Machine has posted eighteen supposed errors (“Why The Media Are Wrong To Rely On Amanda Knox’s Family For Impartial and Accurate Information”) made by Edda Mellas, Amanda Knox’s mother, in an interview on Larry King Live and in other interviews. I invite readers to examine The Machine’s assertions and evaluate their accuracy. Please add citations where appropriate. I’ll get the ball rolling with my replies to numbers 2, 3, and 8, which are given below the three claims made at TJfM.
False claim 2. “He (Rudy Guede) all of a sudden had money that he didn’t have earlier in the day” Edda Mellas is plucking “facts” out thin air with this claim. No evidence was presented at any court hearing that showed that Rudy Guede suddenly had money that he didn’t have earlier in the day on 1 November 2007.
False claim 3. “There is no murder weapon.”
Judge Massei indicates in the sentencing report that Amanda Knox’s judges concluded that the double DNA knife, the larger of the two indicated by Meredith’s autopsy, is indeed the murder weapon. It is totally compatible with the deep puncture wound in Meredith’s neck, and according to a number of independent forensic experts, it contained Meredith’s DNA on the blade.
False claim 8. Rudy Guede’s DNA was in Meredith’s purse.
Edda Mellas’s claim that Rudy Guede’s DNA was in Meredith’s purse is completely untrue. According to the Micheli report, which was made available to the public in January 2008, Guede’s DNA was found on the zip of Meredith’s purse and not inside.
Responses
2. The Machine’s claims about court hearings may be true, but he or she needs to explain where Rudy Guede, who was jobless, obtained the money for a train ticket to Germany. Because the murder occurred at the end of the day on 1 November, Guede’s actions on 2 November and later are equally relevant to a discussion of whether or not he had more money.
3. The Machine does not list these other supposed experts here but does in claim 13. Dr. Stafanoni’s boss, Dr. Renato Biondo, cannot reasonably be called independent. Amanda’s DNA on the handle is strictly meaningless, since we cannot know when it was deposited. The hypothesis that her DNA was deposited when she cooked with the knife is perfectly reasonable. Meredith’s DNA is highly contested. This banal kitchen knife is not compatible with two of the three wounds, and the third one could have been made with any sharp knife, including the one that made the first two.
8. The Machine makes a distinction without a difference. The fact that Rudy Guede’s DNA was found on the zip of Meredith’s purse makes it parsimonious to assume he took Meredith’s money (see claim 2).
Update 1, 4 August 2010
False claim 13: “The DNA is so insignificant. It’s this tiny spot. It’s not blood.” (minute 2.16 above)
Three independent DNA experts - Dr. Patrizia Stefanoni, Dr. Renato Biondo, and Professor Francesca Torricelli - confirmed that Meredith’s DNA was definitely on the blade of the double DNA. The DNA charts themselves show a clear and unmistakable match. Edda Mellas doesn’t seem to understand that DNA evidence almost always involves only microscopic traces of DNA. Dr. Stefanoni testified at the trial that the DNA on the blade could indeed have come from Meredith’s blood.
Response
The Machine ignores that Meredith’s DNA was in the low copy number (LCN) range, demonstrating that he or she understands less about DNA profiling than Edda Mellas does. First, LCN samples should be tested at least twice, and only those alleles that show up in both runs are should be counted. Second, Stefanoni did not use standard LCN conditions in other ways, such as the number of cycles of the amplification step and working under lighting and air-handling conditions that minimize the possibility of DNA contamination. New methods are typically vetted in peer-reviewed journals before they are accepted. Third, the Machine also ignores the well known possibility of contamination, as well as the fact that contamination is a greater risk for samples in the LCN range.
There are some problems with The Machine’s assertion that there is a “clear and unmistakable match.” First, in locus D3S1358 there are two peaks, each with peak height of about 20 RFU, which are not seen in Meredith’s reference profile. They have 15 and 16 repeats, respectively, but Meredith’s profile has peaks at 14 and 18 repeats. Second, in the D21S11 locus, the knife profile has a peak at 30 repeats, but Meredith’s profile has peaks at 30 and 33.2 repeats. It is possible to explain the two extra and one missing peak as a consequence of the DNA being in the LCN range. Yet, this explanation only underscores the fact that Stefanoni should have used the services of a lab that has proper facilities and experience, instead of making up her own inferior method.
It is now well known that Stefanoni went ahead with the analysis, despite the fact that her instrument read “too low,” meaning that there was not enough DNA to continue. What is less well appreciated is the fact that Stefanoni treated this sample differently from other samples, where she discontinued the analysis under similar circumstances. The Machine ignores Stefanoni’s apparent inconsistency.
Dr. Stefanoni’s assertion that the DNA could have come from Meredith’s blood is extremely dubious. The knife tested negative for blood with tetramethylbenzidine (TMB), and Dr. Elizabeth Johnson and Professor Gregory Hampikian indicated that the test for blood is more sensitive than the test for DNA. In other words, if a bloody knife were cleaned of all traces of blood, all traces of DNA would also be removed. They and the cosigners of an open letter on the DNA evidence in this case publish regularly in the field of DNA forensics. The same cannot be said of Dr. Stefanoni.
Furthermore, The Machine ignores the fact that Stefanoni did not turn over the electronic data files or the machine logs. This failure to abide by the international standards of discovery of DNA evidence means that any claim about the quality of the results is suspect. The defense expert witnesses did not have all of the information that they would need to challenge Stefanoni’s dubious results.
Update 2, 4 August 2010, approximately 10:15 PM
“False claim 14: Amanda Knox and Raffaele Sollecito maintained the same story…And most devastating of all, Sollecito stopped providing Knox with an alibi on 5 November 2007.
Sollecito is STILL nearly three years later refusing to corroborate her alibi.”
The Machine’s claim about Raffaele is exactly false. Raffaele backed up Amanda at their hearing in front of Judge Matteini on 8 November 2007, discussed in Darkness Descending on p. 208.
“Judge Matteini said, ‘There are several points, Mr. Sollecito, that differ between your version of today and your version of events as related on the evening of 5 November just three days ago. Can you explain whether you were with Amanda Knox that evening or not?’
Now it was make-or-break time. Matteini had posed the million-dollar question. The one Mignini had been waiting for.
His pay-off was unexpected, effectively an explosive retraction of his initial confession.
Raffaele said, ‘I’m sorry I told you that crap about not being with Amanda. We were together that evening.’
…But now on the key point of the night in question, he was sticking to her like glue again. Backing her up… ‘I can confirm that I spent the night with Amanda Knox.’”
Murder in Italy, p. 198, summarized his appearance before Judge Matteini by noting that Raffaele got the times wrong, but the events right. “Then the judge asked the Italian student what he did remember, prompting a long, dull discussion about the broken pipe under the sink, which he had showed Amanda, discussing with her the probable cause of the leak, a perennial problem in that flat. He also remembered eating dinner with her, watching a movie, working on his computer, getting tired, and going to sleep. Yes of course they slept together. He just couldn’t remember what time they did each action, because he’d been stoned, in a holiday mood, and not punching a time clock.” Finally in his diary Raffaele recalls Amanda saying to him that if she had not been with him that night, she would also be dead.
It is often said that Raffaele did not support Amanda’s alibi of being with him the night of the murder in his appearance before the Supreme Court in the spring of 2008. It was actually Raffaele’s lawyers who appeared, and one of their jobs was to end Raffaele’s detention without charge by any reasonable legal argument. According to Perugia-Shock (25 April 2008) Raffaele’s lawyers invoked the concept of “erroneous assumption,” rather than “erroneous belief.” If they had said “erroneous belief”, it would mean that Amanda was not with him. But the “erroneous assumption” has to do with making an assumption, not so much with the thing being assumed, and then transferring evidence onto him as a result. His lawyers were saying that evidence that might place Amanda at the scene of the crime should not be used to justify holding Raffaele in custody. Raffaele’s lawyers might have meant that Raffaele obviously could not account for Amanda’s whereabouts after he fell asleep. Thus there is no justification for using his lawyers’ appearance before the Supreme Court as evidence that Raffaele claimed that Amanda was elsewhere.
At True Justice for Meredith, The Machine has posted eighteen supposed errors (“Why The Media Are Wrong To Rely On Amanda Knox’s Family For Impartial and Accurate Information”) made by Edda Mellas, Amanda Knox’s mother, in an interview on Larry King Live and in other interviews. I invite readers to examine The Machine’s assertions and evaluate their accuracy. Please add citations where appropriate. I’ll get the ball rolling with my replies to numbers 2, 3, and 8, which are given below the three claims made at TJfM.
False claim 2. “He (Rudy Guede) all of a sudden had money that he didn’t have earlier in the day” Edda Mellas is plucking “facts” out thin air with this claim. No evidence was presented at any court hearing that showed that Rudy Guede suddenly had money that he didn’t have earlier in the day on 1 November 2007.
False claim 3. “There is no murder weapon.”
Judge Massei indicates in the sentencing report that Amanda Knox’s judges concluded that the double DNA knife, the larger of the two indicated by Meredith’s autopsy, is indeed the murder weapon. It is totally compatible with the deep puncture wound in Meredith’s neck, and according to a number of independent forensic experts, it contained Meredith’s DNA on the blade.
False claim 8. Rudy Guede’s DNA was in Meredith’s purse.
Edda Mellas’s claim that Rudy Guede’s DNA was in Meredith’s purse is completely untrue. According to the Micheli report, which was made available to the public in January 2008, Guede’s DNA was found on the zip of Meredith’s purse and not inside.
Responses
2. The Machine’s claims about court hearings may be true, but he or she needs to explain where Rudy Guede, who was jobless, obtained the money for a train ticket to Germany. Because the murder occurred at the end of the day on 1 November, Guede’s actions on 2 November and later are equally relevant to a discussion of whether or not he had more money.
3. The Machine does not list these other supposed experts here but does in claim 13. Dr. Stafanoni’s boss, Dr. Renato Biondo, cannot reasonably be called independent. Amanda’s DNA on the handle is strictly meaningless, since we cannot know when it was deposited. The hypothesis that her DNA was deposited when she cooked with the knife is perfectly reasonable. Meredith’s DNA is highly contested. This banal kitchen knife is not compatible with two of the three wounds, and the third one could have been made with any sharp knife, including the one that made the first two.
8. The Machine makes a distinction without a difference. The fact that Rudy Guede’s DNA was found on the zip of Meredith’s purse makes it parsimonious to assume he took Meredith’s money (see claim 2).
Update 1, 4 August 2010
False claim 13: “The DNA is so insignificant. It’s this tiny spot. It’s not blood.” (minute 2.16 above)
Three independent DNA experts - Dr. Patrizia Stefanoni, Dr. Renato Biondo, and Professor Francesca Torricelli - confirmed that Meredith’s DNA was definitely on the blade of the double DNA. The DNA charts themselves show a clear and unmistakable match. Edda Mellas doesn’t seem to understand that DNA evidence almost always involves only microscopic traces of DNA. Dr. Stefanoni testified at the trial that the DNA on the blade could indeed have come from Meredith’s blood.
Response
The Machine ignores that Meredith’s DNA was in the low copy number (LCN) range, demonstrating that he or she understands less about DNA profiling than Edda Mellas does. First, LCN samples should be tested at least twice, and only those alleles that show up in both runs are should be counted. Second, Stefanoni did not use standard LCN conditions in other ways, such as the number of cycles of the amplification step and working under lighting and air-handling conditions that minimize the possibility of DNA contamination. New methods are typically vetted in peer-reviewed journals before they are accepted. Third, the Machine also ignores the well known possibility of contamination, as well as the fact that contamination is a greater risk for samples in the LCN range.
There are some problems with The Machine’s assertion that there is a “clear and unmistakable match.” First, in locus D3S1358 there are two peaks, each with peak height of about 20 RFU, which are not seen in Meredith’s reference profile. They have 15 and 16 repeats, respectively, but Meredith’s profile has peaks at 14 and 18 repeats. Second, in the D21S11 locus, the knife profile has a peak at 30 repeats, but Meredith’s profile has peaks at 30 and 33.2 repeats. It is possible to explain the two extra and one missing peak as a consequence of the DNA being in the LCN range. Yet, this explanation only underscores the fact that Stefanoni should have used the services of a lab that has proper facilities and experience, instead of making up her own inferior method.
It is now well known that Stefanoni went ahead with the analysis, despite the fact that her instrument read “too low,” meaning that there was not enough DNA to continue. What is less well appreciated is the fact that Stefanoni treated this sample differently from other samples, where she discontinued the analysis under similar circumstances. The Machine ignores Stefanoni’s apparent inconsistency.
Dr. Stefanoni’s assertion that the DNA could have come from Meredith’s blood is extremely dubious. The knife tested negative for blood with tetramethylbenzidine (TMB), and Dr. Elizabeth Johnson and Professor Gregory Hampikian indicated that the test for blood is more sensitive than the test for DNA. In other words, if a bloody knife were cleaned of all traces of blood, all traces of DNA would also be removed. They and the cosigners of an open letter on the DNA evidence in this case publish regularly in the field of DNA forensics. The same cannot be said of Dr. Stefanoni.
Furthermore, The Machine ignores the fact that Stefanoni did not turn over the electronic data files or the machine logs. This failure to abide by the international standards of discovery of DNA evidence means that any claim about the quality of the results is suspect. The defense expert witnesses did not have all of the information that they would need to challenge Stefanoni’s dubious results.
Update 2, 4 August 2010, approximately 10:15 PM
“False claim 14: Amanda Knox and Raffaele Sollecito maintained the same story…And most devastating of all, Sollecito stopped providing Knox with an alibi on 5 November 2007.
Sollecito is STILL nearly three years later refusing to corroborate her alibi.”
The Machine’s claim about Raffaele is exactly false. Raffaele backed up Amanda at their hearing in front of Judge Matteini on 8 November 2007, discussed in Darkness Descending on p. 208.
“Judge Matteini said, ‘There are several points, Mr. Sollecito, that differ between your version of today and your version of events as related on the evening of 5 November just three days ago. Can you explain whether you were with Amanda Knox that evening or not?’
Now it was make-or-break time. Matteini had posed the million-dollar question. The one Mignini had been waiting for.
His pay-off was unexpected, effectively an explosive retraction of his initial confession.
Raffaele said, ‘I’m sorry I told you that crap about not being with Amanda. We were together that evening.’
…But now on the key point of the night in question, he was sticking to her like glue again. Backing her up… ‘I can confirm that I spent the night with Amanda Knox.’”
Murder in Italy, p. 198, summarized his appearance before Judge Matteini by noting that Raffaele got the times wrong, but the events right. “Then the judge asked the Italian student what he did remember, prompting a long, dull discussion about the broken pipe under the sink, which he had showed Amanda, discussing with her the probable cause of the leak, a perennial problem in that flat. He also remembered eating dinner with her, watching a movie, working on his computer, getting tired, and going to sleep. Yes of course they slept together. He just couldn’t remember what time they did each action, because he’d been stoned, in a holiday mood, and not punching a time clock.” Finally in his diary Raffaele recalls Amanda saying to him that if she had not been with him that night, she would also be dead.
It is often said that Raffaele did not support Amanda’s alibi of being with him the night of the murder in his appearance before the Supreme Court in the spring of 2008. It was actually Raffaele’s lawyers who appeared, and one of their jobs was to end Raffaele’s detention without charge by any reasonable legal argument. According to Perugia-Shock (25 April 2008) Raffaele’s lawyers invoked the concept of “erroneous assumption,” rather than “erroneous belief.” If they had said “erroneous belief”, it would mean that Amanda was not with him. But the “erroneous assumption” has to do with making an assumption, not so much with the thing being assumed, and then transferring evidence onto him as a result. His lawyers were saying that evidence that might place Amanda at the scene of the crime should not be used to justify holding Raffaele in custody. Raffaele’s lawyers might have meant that Raffaele obviously could not account for Amanda’s whereabouts after he fell asleep. Thus there is no justification for using his lawyers’ appearance before the Supreme Court as evidence that Raffaele claimed that Amanda was elsewhere.
Tuesday, July 20, 2010
To those who believe that Amanda Knox and Raffaele Sollecito are guilty, I issue a challenge.
Part 20 in the Knox/Sollecito case
Francesco Maresco, lawyer for the Kercher family, said after the verdict last December, “We are teaching the whole world and the United States how to collect, analyse and evaluate scientific technical aspects of the case.”
I have previously discussed how the electronic data files are used by independent experts in criminal cases. Those arguments are especially compelling in the murder of Meredith Kercher, in which the amount of DNA in two of the most important pieces of DNA evidence fall near or into the low copy number (LCN) range. The profile from the bra clasp is also a mixture, and it is well known that the analysis of mixtures introduces subjectivity into the analysis. I have also previously given my reasons for believing that these critical files were never released to the defense teams. Since that time some additional information has become available that puts this question to rest.
Raffaele Sollecito’s appeal documents indicate that his defense expert Dr. Pascali requested the raw data in 2008 (presumably the electronic data files). This request was prior to the preliminary hearing, and the lawyers supported their request with a reference to article 415. They also requested the log files. The judge granted the defense teams the right to forensic information in the summer of 2009 that they had been denied until that time. However, the prosecutions did not fully comply with this order, according to a source close to the defense, and this was one of the things that precipitated the defense teams’ asking for a mistrial in September of 2009.
An open letter coauthored by Dr. Elizabeth Johnson and Professor Gregory Hampikian noted that the prosecution failed to release the electronic data files (.fsa files) to the defense. Since the time of the letter’s release on 11/19/09, some have assumed that these two DNA forensic scientists were unrelated to the case and therefore had no standing to ask for these files. This argument is false. An article written by Fiona Ness on 25 April 2010 indicates that Professor Hampikian is a consultant for Amanda Knox’s defense team. As such, he has every reason to request the operating procedures of the lab, as well as the electronic data files that produce the electropherograms.
“The importance of DNA evidence in a conviction is highlighted in one of Hampikian’s cases - that of US student Amanda Knox. Knox was convicted of the murder of British student Meredith Kercher after a high-profile trial in Italy in 2009. Knox’s conviction was partly based on a sample of her DNA discovered on a knife found in the house. However, Hampikian says he is appalled by the standard of DNA evidence used by the Italian courts to convict Knox in the case. ‘The amount of DNA present is far below the normal cut-off for many labs that I know of. A one off spurious piece of DNA evidence shouldn’t be treated as a gold standard profile from a high-profile source. The issue of this low-template DNA sample is really troubling me.’ Trying to obtain the evidence to have it retested, however, is proving difficult. ‘The discovery rules in Italy are different to what I’m used to. It’s fairly routine in the US that I send a request and get what I want. But in the Knox case I haven’t been able to get a copy of the standard operating procedures of the lab and without that, it’s hard to see if they even followed their own guidelines.’ Evidence, Hampikian says, is a matter of science, to be reviewed, not protected.” (emphasis added) An article in the Irish Times confirms that a professional relationship exists between Professor Hampikian and the Knox family.
The words of an anonymous forensic DNA expert unconnected with the murder of Meredith Kercher are apropos here. This individual said with reference to a different case, “Honest differences of opinion by qualified experts should be welcomed by the Court. This can only be accomplished if the independent expert is provided full and complete discovery by the government.” Keith Inman and Norah Rudin gave ten ways to improve forensic science. Number five was “Provide transparency. Secrecy and gamesmanship are inappropriate to the work of the forensic scientist. All laboratory notes, data, results, procedures, logs, and records should be open to controlled
and appropriate scrutiny.”
To those who believe Ms. Knox and Mr. Sollecito are guilty, I respectfully issue a challenge: Join me in calling for the release of all of the forensic information that the defense has been denied until now. Some among you have argued that the Italian authorities should not release any more information than that demanded by Italian law. However, it is conceivable that Italian law is not yet settled on the question of whether or not to release the electronic data files. If it is not, why should the precedent be against full disclosure rather than in support of full disclosure? If the case against the defendants is as strong as you say it is, you have nothing to fear. On the contrary, your certainty would be stronger if the release and examination of these files produced nothing.
To the Italian authorities I respectfully issue a related challenge: Make good on Mr. Maresca’s claim. Show the world that forensic evidence is to be shared with the defense. At that point the analysis will be complete. Provide the electronic data files (.fsa files), and the instrument log files, and include the contamination log files if they exist. Then and only then will you indeed be showing the world the right way to treat forensic evidence.
Francesco Maresco, lawyer for the Kercher family, said after the verdict last December, “We are teaching the whole world and the United States how to collect, analyse and evaluate scientific technical aspects of the case.”
I have previously discussed how the electronic data files are used by independent experts in criminal cases. Those arguments are especially compelling in the murder of Meredith Kercher, in which the amount of DNA in two of the most important pieces of DNA evidence fall near or into the low copy number (LCN) range. The profile from the bra clasp is also a mixture, and it is well known that the analysis of mixtures introduces subjectivity into the analysis. I have also previously given my reasons for believing that these critical files were never released to the defense teams. Since that time some additional information has become available that puts this question to rest.
Raffaele Sollecito’s appeal documents indicate that his defense expert Dr. Pascali requested the raw data in 2008 (presumably the electronic data files). This request was prior to the preliminary hearing, and the lawyers supported their request with a reference to article 415. They also requested the log files. The judge granted the defense teams the right to forensic information in the summer of 2009 that they had been denied until that time. However, the prosecutions did not fully comply with this order, according to a source close to the defense, and this was one of the things that precipitated the defense teams’ asking for a mistrial in September of 2009.
An open letter coauthored by Dr. Elizabeth Johnson and Professor Gregory Hampikian noted that the prosecution failed to release the electronic data files (.fsa files) to the defense. Since the time of the letter’s release on 11/19/09, some have assumed that these two DNA forensic scientists were unrelated to the case and therefore had no standing to ask for these files. This argument is false. An article written by Fiona Ness on 25 April 2010 indicates that Professor Hampikian is a consultant for Amanda Knox’s defense team. As such, he has every reason to request the operating procedures of the lab, as well as the electronic data files that produce the electropherograms.
“The importance of DNA evidence in a conviction is highlighted in one of Hampikian’s cases - that of US student Amanda Knox. Knox was convicted of the murder of British student Meredith Kercher after a high-profile trial in Italy in 2009. Knox’s conviction was partly based on a sample of her DNA discovered on a knife found in the house. However, Hampikian says he is appalled by the standard of DNA evidence used by the Italian courts to convict Knox in the case. ‘The amount of DNA present is far below the normal cut-off for many labs that I know of. A one off spurious piece of DNA evidence shouldn’t be treated as a gold standard profile from a high-profile source. The issue of this low-template DNA sample is really troubling me.’ Trying to obtain the evidence to have it retested, however, is proving difficult. ‘The discovery rules in Italy are different to what I’m used to. It’s fairly routine in the US that I send a request and get what I want. But in the Knox case I haven’t been able to get a copy of the standard operating procedures of the lab and without that, it’s hard to see if they even followed their own guidelines.’ Evidence, Hampikian says, is a matter of science, to be reviewed, not protected.” (emphasis added) An article in the Irish Times confirms that a professional relationship exists between Professor Hampikian and the Knox family.
The words of an anonymous forensic DNA expert unconnected with the murder of Meredith Kercher are apropos here. This individual said with reference to a different case, “Honest differences of opinion by qualified experts should be welcomed by the Court. This can only be accomplished if the independent expert is provided full and complete discovery by the government.” Keith Inman and Norah Rudin gave ten ways to improve forensic science. Number five was “Provide transparency. Secrecy and gamesmanship are inappropriate to the work of the forensic scientist. All laboratory notes, data, results, procedures, logs, and records should be open to controlled
and appropriate scrutiny.”
To those who believe Ms. Knox and Mr. Sollecito are guilty, I respectfully issue a challenge: Join me in calling for the release of all of the forensic information that the defense has been denied until now. Some among you have argued that the Italian authorities should not release any more information than that demanded by Italian law. However, it is conceivable that Italian law is not yet settled on the question of whether or not to release the electronic data files. If it is not, why should the precedent be against full disclosure rather than in support of full disclosure? If the case against the defendants is as strong as you say it is, you have nothing to fear. On the contrary, your certainty would be stronger if the release and examination of these files produced nothing.
To the Italian authorities I respectfully issue a related challenge: Make good on Mr. Maresca’s claim. Show the world that forensic evidence is to be shared with the defense. At that point the analysis will be complete. Provide the electronic data files (.fsa files), and the instrument log files, and include the contamination log files if they exist. Then and only then will you indeed be showing the world the right way to treat forensic evidence.
Tuesday, July 13, 2010
DNA transfer in Strangulation
Part XIX in the Knox/Sollecito case
Update 1, 22 August 2010
I communicated with an anonymous forensic nurse about their domestic violence program. If an alleged victim complained of an attempted strangulation, complained of a partner’s grabbing their arm, or showed bruising or redness, they have been swabbing that area for DNA, for two years. Positive results in at least one case helped to convict someone. This information confirms the reasonableness of swabbing Meredith’s body in appropriate places, although the bruise on the nape of Meredith’s neck may have been the result of her being thrown against the wall (as some have theorized). We do not know whether swabbing the bruised areas was done or not.
____________________________
PM Guiliano Mignini’s reconstruction of the murder of Meredith Kercher was shown to the jury in the form of an animated video. In his speculation Amanda Knox grabbed Meredith Kercher by the throat and slammed her against a wall. The video superimposed actual shots of Meredith’s bruises with Amanda’s animated hand to imply that Amanda’s action produced the bruises. Later, Rudy Guede and Raffaele Sollecito held Meredith’s arms back, and Amanda stabs her (Barbie Nadeau, Angel Face, p. 160). In forensics professor Carlo Torre’s reconstruction of the crime, the single assailant grabbed Meredith by the throat and stabbed her. The area under Meredith’s chin and her nape were bruised; the former bruising was the result of the knife and the latter when the assailant put Meredith down.
Although Mignini’s theory of the crime suggests a much longer amount of contact between the assailants and victim than does Torre’s, both imply contact. None of Amanda Knox’s DNA was found in Meredith’s bedroom or on her body. Raffaele Sollecito’s DNA was found on a bra clasp (although the defense contests this piece of evidence) but not the bra itself. Rudy Guede’s DNA was found in several places, including on the sleeve of Meredith’s sweatshirt. Let us examine some forensic DNA studies to see if they shed any light on this tragedy.
The study by Wiegand and Kleiber gives a case study in which DNA evidence was collected 48 hours after a strangulation. They wrote, “Strangulation marks were clearly visible on the neck of the victim. Epithelial cells could be removed from the neck of the victim using separate cotton swabs for the left and the right side of the neck. Only the swab from the right side could be typed and included the pattern of the suspect (Fig. 3), a result which corresponded to the autopsy findings (the right neck side showed a higher intensity of bleeding in the muscles than the left side indicating a more intensive pressure against the right side). Altogether clear results could be obtained using four STRs (TH01, VWA, FGA, CD4) demonstrating the high utility and sensitivity of the method described.” These authors also conducted simulated strangulations, and they reported a success rate of better than 70%.
The simulated strangulation study in 2002 by Rutty used both SGMplus and LCN amplification. The simulated strangulation experiment was done with periods between the force and the sampling were 1, 5, 10, 15, 30, and 60 min, 2, 3, 4, 5, 6, 7, 8, 24, and 48 h and 3, 4, 5 and 10 days. When the author used SGMplus, he observed a full profile of the offender 7 out of 29 times, and always in the presence of the victim’s profile. When the author used LCN all 17 experiments yielded offender profiles, with the majority being partial profiles. Dr. Rutty wrote, “Of the test neck swabs, 19 yielded positive amplification results using SGMplus, 12 showed a victim-only profile and 7 a victim and offender profile with a full offender profile detectable up to 6 h after contact. When LCN was used (17 tests) all showed the offender to be present for all time periods i.e. up to 10 days. In the majority of cases it was a partial offender profile with the majority of the amplification result being a full victim profile.”
Dr. Rutty stated that “When considering the apparent time periods of DNA survival, passive transfer of the offender’s DNA onto the victim’s neck could also explain the presence of offender DNA several days after contact.” This study did not break down the results by time periods between simulated strangulation and DNA collection; therefore, it is difficult to draw firm conclusions based solely on the data presented.
A 2008 study by Graham and Rutty reexamined the question of DNA transfer to and from strangulation victims with an emphasis on innocent DNA transfers that might deposit DNA on the neck of a victim. In 24% of samples collected showed nonself DNA on the simulated victim from third party sources. The authors believe that such DNA transfers might confuse an investigation.
Finally, it might be helpful to return to the subject of primary and secondary DNA deposition. The study by Lowe and coworkers in 2002 looked at DNA transfer from a good DNA shedder to a poor DNA shedder to an object. By definition transfer was secondary from the good shedder, and transfer was primary from the poor shedder. When mixtures were observed, secondary transfer from the good shedder provided the major component, not primary transfer from the poor shedder. This study illustrates the dictum that one generally cannot infer the mechanism of how the DNA was deposited from the DNA itself. Along with the study by Graham and Rutty, this work suggests caution in the interpretation of nonself DNA on the body of the victim of strangulation. A similar caution should also be applied in the interpretation of DNA on the bra clasp.
In addition to the case study discussed by Wiegand and Kleiber, there are a small number of news reports of strangulations that mention DNA. One is from greater Detroit, and another is from Chicago. However, these articles do not specify the place on the body that was tested for DNA. In addition to the possibility that DNA was collected from the neck, it is possible that the victim’s fingernails contained the perpetrator’s skin cells or vice versa.
There are no reports that ILE found anyone’s DNA on Meredith’s bare wrists or her neck, and it is unclear whether or not the forensic police swabbed for DNA in these areas. It is also unclear whether some areas on the neck would have been free enough of Meredith’s blood to allow swabbing for the assailant’s DNA. Nevertheless it is difficult to see why the forensic police should not have swabbed the nape of Meredith’s neck or her wrists. If they did and found nothing, it would be strongly exculpatory, although it might fall short of proof of innocence due to uncertainties over collecting enough DNA or collecting it quickly enough after the murder. If the forensic police failed to swab these areas, it would suggest that they did not do as thorough a job as one would wish.
Bibliography
P. Wiegand and M. Kleiber, “DNA typing of epithelial cells after strangulation,” International Journal of Legal Medicine (1997) 110 :181–183. abstract
G. N. Rutty, “An investigation into the transference and survivability
of human DNA following simulated manual strangulation
with consideration of the problem of third party contamination,” International Journal of Legal Medicine (2002) 116 :170–173.
abstract
A. Lowe, C. Murray, J. Whitaker, G. Tully, P. Gill, “The propensity of individuals to deposit DNA and secondary transfer of low level DNA from individuals to inert surfaces.” Forensic Science International (2002) 129(1):25-34. abstract
E. A. M. Graham and G.N. Rutty, “Investigation into ‘normal’ background DNA on adult necks: implications for DNA profiling of manual strangulation victims.” Journal of Forensic Science, (2008) 53(5):1074-82. abstract
Update 1, 22 August 2010
I communicated with an anonymous forensic nurse about their domestic violence program. If an alleged victim complained of an attempted strangulation, complained of a partner’s grabbing their arm, or showed bruising or redness, they have been swabbing that area for DNA, for two years. Positive results in at least one case helped to convict someone. This information confirms the reasonableness of swabbing Meredith’s body in appropriate places, although the bruise on the nape of Meredith’s neck may have been the result of her being thrown against the wall (as some have theorized). We do not know whether swabbing the bruised areas was done or not.
____________________________
PM Guiliano Mignini’s reconstruction of the murder of Meredith Kercher was shown to the jury in the form of an animated video. In his speculation Amanda Knox grabbed Meredith Kercher by the throat and slammed her against a wall. The video superimposed actual shots of Meredith’s bruises with Amanda’s animated hand to imply that Amanda’s action produced the bruises. Later, Rudy Guede and Raffaele Sollecito held Meredith’s arms back, and Amanda stabs her (Barbie Nadeau, Angel Face, p. 160). In forensics professor Carlo Torre’s reconstruction of the crime, the single assailant grabbed Meredith by the throat and stabbed her. The area under Meredith’s chin and her nape were bruised; the former bruising was the result of the knife and the latter when the assailant put Meredith down.
Although Mignini’s theory of the crime suggests a much longer amount of contact between the assailants and victim than does Torre’s, both imply contact. None of Amanda Knox’s DNA was found in Meredith’s bedroom or on her body. Raffaele Sollecito’s DNA was found on a bra clasp (although the defense contests this piece of evidence) but not the bra itself. Rudy Guede’s DNA was found in several places, including on the sleeve of Meredith’s sweatshirt. Let us examine some forensic DNA studies to see if they shed any light on this tragedy.
The study by Wiegand and Kleiber gives a case study in which DNA evidence was collected 48 hours after a strangulation. They wrote, “Strangulation marks were clearly visible on the neck of the victim. Epithelial cells could be removed from the neck of the victim using separate cotton swabs for the left and the right side of the neck. Only the swab from the right side could be typed and included the pattern of the suspect (Fig. 3), a result which corresponded to the autopsy findings (the right neck side showed a higher intensity of bleeding in the muscles than the left side indicating a more intensive pressure against the right side). Altogether clear results could be obtained using four STRs (TH01, VWA, FGA, CD4) demonstrating the high utility and sensitivity of the method described.” These authors also conducted simulated strangulations, and they reported a success rate of better than 70%.
The simulated strangulation study in 2002 by Rutty used both SGMplus and LCN amplification. The simulated strangulation experiment was done with periods between the force and the sampling were 1, 5, 10, 15, 30, and 60 min, 2, 3, 4, 5, 6, 7, 8, 24, and 48 h and 3, 4, 5 and 10 days. When the author used SGMplus, he observed a full profile of the offender 7 out of 29 times, and always in the presence of the victim’s profile. When the author used LCN all 17 experiments yielded offender profiles, with the majority being partial profiles. Dr. Rutty wrote, “Of the test neck swabs, 19 yielded positive amplification results using SGMplus, 12 showed a victim-only profile and 7 a victim and offender profile with a full offender profile detectable up to 6 h after contact. When LCN was used (17 tests) all showed the offender to be present for all time periods i.e. up to 10 days. In the majority of cases it was a partial offender profile with the majority of the amplification result being a full victim profile.”
Dr. Rutty stated that “When considering the apparent time periods of DNA survival, passive transfer of the offender’s DNA onto the victim’s neck could also explain the presence of offender DNA several days after contact.” This study did not break down the results by time periods between simulated strangulation and DNA collection; therefore, it is difficult to draw firm conclusions based solely on the data presented.
A 2008 study by Graham and Rutty reexamined the question of DNA transfer to and from strangulation victims with an emphasis on innocent DNA transfers that might deposit DNA on the neck of a victim. In 24% of samples collected showed nonself DNA on the simulated victim from third party sources. The authors believe that such DNA transfers might confuse an investigation.
Finally, it might be helpful to return to the subject of primary and secondary DNA deposition. The study by Lowe and coworkers in 2002 looked at DNA transfer from a good DNA shedder to a poor DNA shedder to an object. By definition transfer was secondary from the good shedder, and transfer was primary from the poor shedder. When mixtures were observed, secondary transfer from the good shedder provided the major component, not primary transfer from the poor shedder. This study illustrates the dictum that one generally cannot infer the mechanism of how the DNA was deposited from the DNA itself. Along with the study by Graham and Rutty, this work suggests caution in the interpretation of nonself DNA on the body of the victim of strangulation. A similar caution should also be applied in the interpretation of DNA on the bra clasp.
In addition to the case study discussed by Wiegand and Kleiber, there are a small number of news reports of strangulations that mention DNA. One is from greater Detroit, and another is from Chicago. However, these articles do not specify the place on the body that was tested for DNA. In addition to the possibility that DNA was collected from the neck, it is possible that the victim’s fingernails contained the perpetrator’s skin cells or vice versa.
There are no reports that ILE found anyone’s DNA on Meredith’s bare wrists or her neck, and it is unclear whether or not the forensic police swabbed for DNA in these areas. It is also unclear whether some areas on the neck would have been free enough of Meredith’s blood to allow swabbing for the assailant’s DNA. Nevertheless it is difficult to see why the forensic police should not have swabbed the nape of Meredith’s neck or her wrists. If they did and found nothing, it would be strongly exculpatory, although it might fall short of proof of innocence due to uncertainties over collecting enough DNA or collecting it quickly enough after the murder. If the forensic police failed to swab these areas, it would suggest that they did not do as thorough a job as one would wish.
Bibliography
P. Wiegand and M. Kleiber, “DNA typing of epithelial cells after strangulation,” International Journal of Legal Medicine (1997) 110 :181–183. abstract
G. N. Rutty, “An investigation into the transference and survivability
of human DNA following simulated manual strangulation
with consideration of the problem of third party contamination,” International Journal of Legal Medicine (2002) 116 :170–173.
abstract
A. Lowe, C. Murray, J. Whitaker, G. Tully, P. Gill, “The propensity of individuals to deposit DNA and secondary transfer of low level DNA from individuals to inert surfaces.” Forensic Science International (2002) 129(1):25-34. abstract
E. A. M. Graham and G.N. Rutty, “Investigation into ‘normal’ background DNA on adult necks: implications for DNA profiling of manual strangulation victims.” Journal of Forensic Science, (2008) 53(5):1074-82. abstract
Monday, June 21, 2010
Raffaele Sollecito's Appeal
Part XVIII in the Knox/Sollecito case
Update, 7/12/10
Here is a better translation of a portion of Sollecito’s appeal dealing with the bra clasp, provided by an anonymous translator:
“But there is more. The lack of full discovery was also found during the course of the trial:
- on July 18 2009, during cross-examination of the technical consultant of Raffaele Sollecito’s defence, Prof. Adriano Tagliabracci, there was an astonishing coup de theatre, in which the prosecution formulated a question which generated the suspicion that the Public Minister was in possession of further laboratory data never made available to the defence. In particular, the data relative to the quantity of the extract used for genetic analysis of the biological material found on the bra clasp of the victim;
- confronted with the reaction of the defence, the office of the Public Minister had to admit that there existed documents compiled by the scientific police never deposited at the conclusion of the investigations (contravening in this way the provision of Article 415 bis c.p.p.), nor sent to the Gup with the request for trial (in violation of Article 416, paragraph 2, c.p.p.).
In other words, the office of the PM denied a complete discovery of the documents of the investigation, extending this breach in the rights of the defence into the trial!”
This passage indicates that the prosecution failed to provide the defense with information relating to the single most important piece of evidence against Raffaele Sollecito all through the pre-trial and well into the trial phase. What is unclear from the appeal document alone is whether or not all information was ultimately released. However, other documents indicate that the prosecution never released all of the information that the defense teams sought.
___________________________________________________
The following is Google-translated from Raffaele's appeal document (pp. 51-57) with some minor edits. Although it is hard to decipher the meaning in places, it gives a picture of the defense continually asking for information on the DNA testing all throughout the preliminary hearing and trial, and the prosecution continually refusing. I have previously written about the importance of the electronic data files to a proper defense and about the near universality of this disclosure. I am eager to hear the prosecution’s explanation of how their refusal to hand over log files and electronic data files can be anything other than a trampling upon the right of discovery:
“And there is no doubt that, in terms of 'prosecution, failure to discovery on one of the main aspects of the process has been a considerable advantage over the defense, since the case involved Raffaele Sollecito is building right on genetic testing. In fact, it is useful to make a historical reconstruction of the case at hand:
- Following the conclusion of preliminary investigations, the defense could review the technical report of forensic genetic investigations in the signature of Dr. Patrizia Stefanoni, to which were attached tables who reported only the number of alleles, without which they would specify any other information or scientific data (for clarity, we define each variant allele of a gene, the genotype of an individual gene has a relatively Kit alleles he is in possession);
- Given the extreme importance of this for proof on indication of Prof. Pascali expert defense Raffaele Reminder, on June 24, 2008 - pending the period of 20 days under Article. 415 bis -, was made an initial request to Prosecutor acquisition diagrams in electropherograms whereby the forensic results came in content Technical report on forensic genetics. In particular, this request is have specified the absolute necessity (in order of presentation defensive pleadings and petitions under Article. 415 bis cpp) to have the aforementioned documents available to the consultant of the could examine it in detail;
- However, against all evidence, the prosecutor dismissed the request was deemed inadmissible 'because the option in all.art.415 cpp a cover secured and only those acts ';
- To deal with a similar unjust refusal, the defense made on July 3, 2008, a further instance in which it sought to 'acquire forensic laboratories of the numerical values and RFU peaks on all findings, or alternatively to obtain police Scientific CDROM containing the raw data and peak RFU. It was asked, Moreover, in case it was not possible to obtain copies of these data, that the Prof. Pascali was allowed to go to the police service science for a spot inspection of the data and make it directly computerized copy;
- Even that request, however, was inexplicably rejected on 11 July 2008 with the anodyne statement that 'on the charts of Forensic there are already bars with generic value on fluorescence peaks.
The defense then returned to a preliminary hearing with a serious cognitive gap, due to lack of awareness of scientific data used by the police in their scientific investigations. As we shall see, this story had a further follow:
- Preliminary hearing of 16 September 2008, the defense reiterated request to acquire numerical values RFU and peaks at all findings or, alternatively, to acquire the CD-ROM containing the raw data RFU and peaks. The request filed at that meeting was based upon both the incompleteness detected in the diagrams attached to the report, and by the repeated requests made to the office of the C>P> to obtain the missing data;
- After this request, the Gup could not help but detect need 'for purposes of deciding' to understand 'fully (...) as procedure has been adopted for the analysis in question, and whether there further elaborations that constitute the necessary support conclusions reached. 'Consequently, the Gup has ordered the hearing in heard of Dr. Stefanoni calling 'to accompany their testimony with computer media containing data requested by the defense. "The same judge in that case was aware the extreme importance of data capture whereas the investigations living would receive 'the most important elements all.impianto accusatory;
- On September 25, 2008 in observance of the provision of Gup is was deposited by association. Zugarini on behalf of Dr. Stefanoni, the CD-Rom containing the requested data. In this regard like to highlight as the immediate acceptance of the instance in question proves unequivocally from the outset the importance of having the data available full scientific;
- Hearing on September 27, 2008, was then represented to the Gup need to obtain additional documentation because incomplete data, therefore, was asked to Court to acquire the service files (log files);
- However, the Judge, after seeking an opinion to Dr. Stefanoni has also rejected the application based on an uncritical adherence to its comments, coming to claim that "not be needed information contained in the logs (data nell.esperienza forensic are never identified, resulting standards approved by the parameters internationally and which appear to be in use in all Laboratories engaged in Forensic Genetics).
Such an established procedure is not, of course, acceptable under no point of view, since the unconditional adherence to observations of Dr. Stefanoni, has led to support the contention accusatory, without the technical-scientific comparison of an expert third and impartial.
And indeed, if it had consulted a person not bound by any constraint on the charge (ie a neutral), the parties would certainly have benefitted. And 'quite clear that to ask to review its person (Dr Stefanoni) which produced that result is, in fact, nonsense: can not say, claim of self-discipline science by the same technician who testified that result. Any specialist will of course be pushed, albeit inadvertently, to defend the validity of their work, even in front of a simple request for clarification, and justify - after all, understandably, by his point of view - that all data provided are sufficient.
Was evidence showed the need to provide all documentation scientific defense.
It 'important to note that log files are much scientific data relevant, if not indispensable, especially in situations (such as the case in point) where the peak height must be assessed together with other parameters (such as area) is also higher to determine the plausibility or, conversely, the unlikelihood attribution to a person's DNA. So it is true that during the preliminary hearing in court, the Dr. Stefanoni - at the request of the consultant that the Prosecution asked if it was important given the "peak area" – said "Normally not. "However, what is more surprising is that the very Dr. Stefanoni candidly admitted that it had no other experiences on (p. 68 transcription.'s preliminary hearing Oct. 4, 2009). The opinion of Dr. Stefanoni, in fact, emerged in all its fragility when the consultant has made the defense Reminder noted a recommendation of the International Society of Genetic Lawyers, which states that the method used to interpret traces of mixed DNA and consider l.area l.altezza of peaks "(p. 99 of those transcripts.)
The GUP at this point, he invited Dr. Stefanoni to be received by October 8, 'the data relating to the calculation of peak areas related to the finding 165 / B indicated by prof. Pascali in the third column, in his name, all.allegato referred to the report filed, and diagram on the second run on the sample elettroferografica 36B.
The epilogue of this long run-up occurred on October 8, 2008 with the filing by Dr. Stefanoni the CD-ROM containing the data dell.amplificato electrophoresis sample DNA called 165 / B (finding piece of cloth with hooks), and the CD-Rom containing: Sample data info for the two races dell.amplificato electrophoretic sample of DNA known as 36 / B (Finding knife) electropherograms of the second electrophoresis.
As can be seen from the picture just outlined, the defense did not have provision, at the conclusion of preliminary investigations, all acts of investigation as required by law, so much so that this uncertainty lasted at least for the preliminary hearing stage (and beyond, as you say).
For example, consider the simple analysis of the peak - technical data that was provided to the defense until after the hearing at the hearing Preliminary Dr. Stefanoni, damaging irreparably the rights of defense -revealed that the amount of DNA used for analysis was quite modest, which led the consultant to the defense clarified, that the interpretation given to the forensic graphics has minimally complied with the guidelines laid down by the International Society of Forensic Genetics.
But there is more. The lack of full discovery was also found in during the process:
- On July 18, 2009, during cross-examination technical consultant Defense Raffaele Sollecito, Professor Adriano Tagliabracci, there was an astonishing coup de théâtre, as the accusation made questions that have created the suspicion that the prosecutor had hold additional laboratory data ever made available to parties. It was, in particular, data on the amount of extract used for genetic analysis of biological material found on the hook of the bra of the victim;
- In front of the defense reaction, the Office of Public Prosecutor had to admit that there are acts performed by forensic ever deposited at the conclusion of the investigation (in contravention Thus the provision of art. 415 bis cpp) or sent to Gup with the request of trial (in violation of Article. 416, paragraph 2, cpp).
In other words, the Office of the PM or denied full discovery of documents investigation, pushing this lesion of the right of defense to the debate! We will now give an account of evaluations of the Court of Assizes of Perugia. The sentence I can refer about the motivations of the order of rejection "of All.audience 14/09/2009 defenses of the defendants objected l.avv n the interference with the right defense, arguing in this regard, which were verified the void. After hearing the other party seeking to disregard l.exception, this Court issued l.decree, which read out with which l.exception of nullity was rejected and was available to proceed further "(p.7. above).
Passing the order of 14 September 2009, the Assize Court noted as follows: 'respect of invalidity l.exception advanced and illustrated memory today filed for violation of the right of defense question exception is not admissible, l.activity sampling and comparison of traces biological object activity.exception the nature of prior technical investigation covered with the possibility dall.article 360 for parties to participate in and comment in this context is not apparent that there has been no lesion of the right of defense, for the nullity that would assessed in a case of a 415 dell.article knows nzione not provided by any specific provision or by a 415 Criminal Procedure Code that principle of mandatory nature of the void during preliminary dell.audience compare 1/10/2008 GUP measure included in documents filed today in support the plea of nullity that aspect has been addressed and its exception has not been repeated in terms of which all.article Code 491 Nell.audience of Criminal Procedure also before this Court on 18.7.2009 issue was not raised in terms of the void under the compare the transcripts of the hearing on 18.7.2009, with particular Refer to pages 102 et seq and 114 et seq therefore logical to conclude that l.aspect in all.exception now advances to integrate a nullity ta question But to sanction by the Supreme Court ruled on the matter for example compare Cassation Judgement second section 29573 of 2006 and Section Supreme number 21593 2009 its fifth exception was belatedly raised. As for the broken and also being the subject of advanced today than that penalty is justified in the presence of a omitted on filing all.entire investigations in this case l.omission h a covered part of the supporting documentation'”
Update, 7/12/10
Here is a better translation of a portion of Sollecito’s appeal dealing with the bra clasp, provided by an anonymous translator:
“But there is more. The lack of full discovery was also found during the course of the trial:
- on July 18 2009, during cross-examination of the technical consultant of Raffaele Sollecito’s defence, Prof. Adriano Tagliabracci, there was an astonishing coup de theatre, in which the prosecution formulated a question which generated the suspicion that the Public Minister was in possession of further laboratory data never made available to the defence. In particular, the data relative to the quantity of the extract used for genetic analysis of the biological material found on the bra clasp of the victim;
- confronted with the reaction of the defence, the office of the Public Minister had to admit that there existed documents compiled by the scientific police never deposited at the conclusion of the investigations (contravening in this way the provision of Article 415 bis c.p.p.), nor sent to the Gup with the request for trial (in violation of Article 416, paragraph 2, c.p.p.).
In other words, the office of the PM denied a complete discovery of the documents of the investigation, extending this breach in the rights of the defence into the trial!”
This passage indicates that the prosecution failed to provide the defense with information relating to the single most important piece of evidence against Raffaele Sollecito all through the pre-trial and well into the trial phase. What is unclear from the appeal document alone is whether or not all information was ultimately released. However, other documents indicate that the prosecution never released all of the information that the defense teams sought.
___________________________________________________
The following is Google-translated from Raffaele's appeal document (pp. 51-57) with some minor edits. Although it is hard to decipher the meaning in places, it gives a picture of the defense continually asking for information on the DNA testing all throughout the preliminary hearing and trial, and the prosecution continually refusing. I have previously written about the importance of the electronic data files to a proper defense and about the near universality of this disclosure. I am eager to hear the prosecution’s explanation of how their refusal to hand over log files and electronic data files can be anything other than a trampling upon the right of discovery:
“And there is no doubt that, in terms of 'prosecution, failure to discovery on one of the main aspects of the process has been a considerable advantage over the defense, since the case involved Raffaele Sollecito is building right on genetic testing. In fact, it is useful to make a historical reconstruction of the case at hand:
- Following the conclusion of preliminary investigations, the defense could review the technical report of forensic genetic investigations in the signature of Dr. Patrizia Stefanoni, to which were attached tables who reported only the number of alleles, without which they would specify any other information or scientific data (for clarity, we define each variant allele of a gene, the genotype of an individual gene has a relatively Kit alleles he is in possession);
- Given the extreme importance of this for proof on indication of Prof. Pascali expert defense Raffaele Reminder, on June 24, 2008 - pending the period of 20 days under Article. 415 bis -, was made an initial request to Prosecutor acquisition diagrams in electropherograms whereby the forensic results came in content Technical report on forensic genetics. In particular, this request is have specified the absolute necessity (in order of presentation defensive pleadings and petitions under Article. 415 bis cpp) to have the aforementioned documents available to the consultant of the could examine it in detail;
- However, against all evidence, the prosecutor dismissed the request was deemed inadmissible 'because the option in all.art.415 cpp a cover secured and only those acts ';
- To deal with a similar unjust refusal, the defense made on July 3, 2008, a further instance in which it sought to 'acquire forensic laboratories of the numerical values and RFU peaks on all findings, or alternatively to obtain police Scientific CDROM containing the raw data and peak RFU. It was asked, Moreover, in case it was not possible to obtain copies of these data, that the Prof. Pascali was allowed to go to the police service science for a spot inspection of the data and make it directly computerized copy;
- Even that request, however, was inexplicably rejected on 11 July 2008 with the anodyne statement that 'on the charts of Forensic there are already bars with generic value on fluorescence peaks.
The defense then returned to a preliminary hearing with a serious cognitive gap, due to lack of awareness of scientific data used by the police in their scientific investigations. As we shall see, this story had a further follow:
- Preliminary hearing of 16 September 2008, the defense reiterated request to acquire numerical values RFU and peaks at all findings or, alternatively, to acquire the CD-ROM containing the raw data RFU and peaks. The request filed at that meeting was based upon both the incompleteness detected in the diagrams attached to the report, and by the repeated requests made to the office of the C>P> to obtain the missing data;
- After this request, the Gup could not help but detect need 'for purposes of deciding' to understand 'fully (...) as procedure has been adopted for the analysis in question, and whether there further elaborations that constitute the necessary support conclusions reached. 'Consequently, the Gup has ordered the hearing in heard of Dr. Stefanoni calling 'to accompany their testimony with computer media containing data requested by the defense. "The same judge in that case was aware the extreme importance of data capture whereas the investigations living would receive 'the most important elements all.impianto accusatory;
- On September 25, 2008 in observance of the provision of Gup is was deposited by association. Zugarini on behalf of Dr. Stefanoni, the CD-Rom containing the requested data. In this regard like to highlight as the immediate acceptance of the instance in question proves unequivocally from the outset the importance of having the data available full scientific;
- Hearing on September 27, 2008, was then represented to the Gup need to obtain additional documentation because incomplete data, therefore, was asked to Court to acquire the service files (log files);
- However, the Judge, after seeking an opinion to Dr. Stefanoni has also rejected the application based on an uncritical adherence to its comments, coming to claim that "not be needed information contained in the logs (data nell.esperienza forensic are never identified, resulting standards approved by the parameters internationally and which appear to be in use in all Laboratories engaged in Forensic Genetics).
Such an established procedure is not, of course, acceptable under no point of view, since the unconditional adherence to observations of Dr. Stefanoni, has led to support the contention accusatory, without the technical-scientific comparison of an expert third and impartial.
And indeed, if it had consulted a person not bound by any constraint on the charge (ie a neutral), the parties would certainly have benefitted. And 'quite clear that to ask to review its person (Dr Stefanoni) which produced that result is, in fact, nonsense: can not say, claim of self-discipline science by the same technician who testified that result. Any specialist will of course be pushed, albeit inadvertently, to defend the validity of their work, even in front of a simple request for clarification, and justify - after all, understandably, by his point of view - that all data provided are sufficient.
Was evidence showed the need to provide all documentation scientific defense.
It 'important to note that log files are much scientific data relevant, if not indispensable, especially in situations (such as the case in point) where the peak height must be assessed together with other parameters (such as area) is also higher to determine the plausibility or, conversely, the unlikelihood attribution to a person's DNA. So it is true that during the preliminary hearing in court, the Dr. Stefanoni - at the request of the consultant that the Prosecution asked if it was important given the "peak area" – said "Normally not. "However, what is more surprising is that the very Dr. Stefanoni candidly admitted that it had no other experiences on (p. 68 transcription.'s preliminary hearing Oct. 4, 2009). The opinion of Dr. Stefanoni, in fact, emerged in all its fragility when the consultant has made the defense Reminder noted a recommendation of the International Society of Genetic Lawyers, which states that the method used to interpret traces of mixed DNA and consider l.area l.altezza of peaks "(p. 99 of those transcripts.)
The GUP at this point, he invited Dr. Stefanoni to be received by October 8, 'the data relating to the calculation of peak areas related to the finding 165 / B indicated by prof. Pascali in the third column, in his name, all.allegato referred to the report filed, and diagram on the second run on the sample elettroferografica 36B.
The epilogue of this long run-up occurred on October 8, 2008 with the filing by Dr. Stefanoni the CD-ROM containing the data dell.amplificato electrophoresis sample DNA called 165 / B (finding piece of cloth with hooks), and the CD-Rom containing: Sample data info for the two races dell.amplificato electrophoretic sample of DNA known as 36 / B (Finding knife) electropherograms of the second electrophoresis.
As can be seen from the picture just outlined, the defense did not have provision, at the conclusion of preliminary investigations, all acts of investigation as required by law, so much so that this uncertainty lasted at least for the preliminary hearing stage (and beyond, as you say).
For example, consider the simple analysis of the peak - technical data that was provided to the defense until after the hearing at the hearing Preliminary Dr. Stefanoni, damaging irreparably the rights of defense -revealed that the amount of DNA used for analysis was quite modest, which led the consultant to the defense clarified, that the interpretation given to the forensic graphics has minimally complied with the guidelines laid down by the International Society of Forensic Genetics.
But there is more. The lack of full discovery was also found in during the process:
- On July 18, 2009, during cross-examination technical consultant Defense Raffaele Sollecito, Professor Adriano Tagliabracci, there was an astonishing coup de théâtre, as the accusation made questions that have created the suspicion that the prosecutor had hold additional laboratory data ever made available to parties. It was, in particular, data on the amount of extract used for genetic analysis of biological material found on the hook of the bra of the victim;
- In front of the defense reaction, the Office of Public Prosecutor had to admit that there are acts performed by forensic ever deposited at the conclusion of the investigation (in contravention Thus the provision of art. 415 bis cpp) or sent to Gup with the request of trial (in violation of Article. 416, paragraph 2, cpp).
In other words, the Office of the PM or denied full discovery of documents investigation, pushing this lesion of the right of defense to the debate! We will now give an account of evaluations of the Court of Assizes of Perugia. The sentence I can refer about the motivations of the order of rejection "of All.audience 14/09/2009 defenses of the defendants objected l.avv n the interference with the right defense, arguing in this regard, which were verified the void. After hearing the other party seeking to disregard l.exception, this Court issued l.decree, which read out with which l.exception of nullity was rejected and was available to proceed further "(p.7. above).
Passing the order of 14 September 2009, the Assize Court noted as follows: 'respect of invalidity l.exception advanced and illustrated memory today filed for violation of the right of defense question exception is not admissible, l.activity sampling and comparison of traces biological object activity.exception the nature of prior technical investigation covered with the possibility dall.article 360 for parties to participate in and comment in this context is not apparent that there has been no lesion of the right of defense, for the nullity that would assessed in a case of a 415 dell.article knows nzione not provided by any specific provision or by a 415 Criminal Procedure Code that principle of mandatory nature of the void during preliminary dell.audience compare 1/10/2008 GUP measure included in documents filed today in support the plea of nullity that aspect has been addressed and its exception has not been repeated in terms of which all.article Code 491 Nell.audience of Criminal Procedure also before this Court on 18.7.2009 issue was not raised in terms of the void under the compare the transcripts of the hearing on 18.7.2009, with particular Refer to pages 102 et seq and 114 et seq therefore logical to conclude that l.aspect in all.exception now advances to integrate a nullity ta question But to sanction by the Supreme Court ruled on the matter for example compare Cassation Judgement second section 29573 of 2006 and Section Supreme number 21593 2009 its fifth exception was belatedly raised. As for the broken and also being the subject of advanced today than that penalty is justified in the presence of a omitted on filing all.entire investigations in this case l.omission h a covered part of the supporting documentation'”
Wednesday, June 16, 2010
DNA contamination and DNA cold hits
Part XVII in the Knox/Sollecito case
This post returns to the problem of forensic DNA contamination. It also addresses the problem of partial profiles and adventitious matches, especially with respect to cold cases. North Carolinians might want to take special note of the John Puckett and Raymond Easton cases, inasmuch as North Carolina may join other states in demanding DNA samples upon arrest. My prediction is that as the size of a DNA database grows, we will see a greater number of cold case convictions that turn out to be erroneous.
Murder of Jane Mixer
We have previously encountered the conviction of Gary Leiterman of the murder of Jane Mixer. The presence of both Mr. Leiterman’s DNA and that of John Ruelas. The prosecution was unable to come up with a reasonable explanation for Mr. Ruelas’ DNA; he was four years old at the time and lived in another city.
Dr. Theodore Kessis reexamined the DNA forensics of this case:
“Review of the electropherograms associated with this negative control sample (NEG 041902) reveals that it was contaminated, a fact that cannot be disputed since Dr. Milligan himself labeled it with a note indicating as much (Appendix 8 - Electropherogram sample NEG 041902).
Remarkably, Dr. Milligan stated in his 7/15/02 testimony that no contamination events had occurred during the course of his testing and that if any had, he would have documented them in his reports (pg. 141-21 and 142-4). Equally difficult to rectify here is the fact that when asked if he had ever committed an error, Dr. Milligan's replied he could never recall making one. (pg. 162, lines 1-5)”
While agreeing with others that most contamination events happen when two samples are handled closely in space and time, Dr. Kessis also offered a caution, “It must be noted however that contamination errors have been documented where no direct processing link between sample and contaminant have been established, raising the specter that a source of contamination can linger in a laboratory for some time.”
Dr. Kessis found another deficiency: “As previously mentioned, Corrective Action files and Error logs form an important part of a laboratory's quality control and assurance programs by centralizing the documentation of errors within the laboratory. Mandated by the DAB Standards (Appendix 2, section 14.1.1), such data allows laboratory management to quickly and efficiently identify and address systematic problems that affect the reliability of testing results.”
“Given the thousands of samples, hundreds of cases, and number of people handling casework within this laboratory, the lack of a centralize system to track errors and discrepancy indicates that the lab had no mechanism in place to identify and deal with systematic problems such as contamination events.”
There are several take-home messages for students of the Knox/Sollecito case here. Contamination by more than one individual’s DNA is possible. The laboratories in question will sometimes claim to be error-free, as did the Rome lab. In such an instance it would be helpful to check the laboratory’s corrective action files, which are more likely to be accurate than someone’s memory. Whether the Rome lab has such files is unclear. Finally, when DNA results force one to an absurd conclusion (as with the kitchen knife), contamination or misinterpretation should be suspected.
The case of Gregory Turner
Gregory Turner was indicted and jailed for a murder when the DNA from a murdered woman in Newfoundland was found on his wedding ring. The ring also contained DNA from one other contributor, thought to be his accomplice. However, the lawyer sought out the names of the technicians from the lab and determined that the technician working on his ring also worked on the victim’s fingernails. Moreover, the DNA from the second contributor to the ring turned out to be the profile of the technician herself. After many months, Mr. Turner was released from jail. This particular case of DNA contamination is an example of where both primary and secondary transfer of DNA occurred. As did the Mixer case, it shows that contamination can transfer the DNA from more than one person onto an item of evidence. This is worth bearing in mind given the multiple DNA contributors to the bra clasp in the Knox/Sollecito case.
Profile N
As was true in the Jaidyn Leskie case, the victim of one crime can become a suspect in other crimes on the basis of contaminated DNA evidence. Sometimes it takes a major foul-up to prod a laboratory into corrective action. In New Zealand, the Wellington police were investigating two murders, dubbed Rex and Pad, as well as N, the victim of an assault.
Michael Strutt reported, “One caught up in the testing was a mild mannered Christchurch man who had been assaulted outside his local, the Hagley Arms Hotel, on 23 April 1998. Police had taken blood in order to eliminate his DNA from samples taken from the scene of the assault and sent it to ESR for testing. The result of this test came to be dubbed 'Profile N' by the inquiries which were to follow… The Christchurch assault victim was subjected to 'extensive police inquiries' for more than three months and his financial records were seized. This established what he had claimed all along, that he had not left Christchurch around the time of the murders. In fact he hardly left Christchurch at all… Although they never discovered exactly how the mistakes had happened they did determine that the 'Rex' and 'Pad' samples had been accidentally contaminated with DNA from Profile N at an early stage of processing at ESR's Mt Albert laboratories. Extracts from them sent to other laboratories for testing also returned Profile N. Numerous recommendations for improving oversight, record keeping and even laboratory ventilation were made.”
“During the inquiry ESR [Environmental Science & Research Ltd] was asked to check the results of all testing done in July 1998 for any further instances of Profile N. Although they initially reported that none were found, later retests showed a partial profile consistent with N in another sample from 'Pad'. They also revealed 25 other 'unexplained' profiles in 14 of the 36 samples tested that month.”
A group investigating these cases asked a manager of the forensic unit of the ESR lab to comment, “The Wellington murders you refer to were not DNA failures. The problem was picked up and investigated. Five separate investigations failed to find scientific proof for the cause of the anomalies. No direct evidence of either accidental or deliberate contamination has come to light. Existing facilities and protocols were shown to meet independent quality audit requirements. The Ministerial Inquiry recognising the points above concluded that on the balance of probabilities the apparently anomalous results could be ascribed to accidental contamination of DNA extracts within the ESR laboratory. They made a number of recommendations which ESR has either implemented or is planning to implement. This sits comfortably with our continuous improvement management focus.”
The fact that the lab in question met the audit requirements is evidence that simply following accepted protocols does not guarantee that contamination will never happen. The lack of the determination of an exact mechanism of contamination is consistent with Dr. Kessis’s caution in the Mixer case above. People who argue that Amanda Knox and Raffaele Sollecito are guilty sometimes demand a mechanism of contamination; unfortunately, this cannot always be determined.
The first false cold hit case in the UK
Michael Strutt wrote, “A man [Raymond Easton] with advanced Parkinsons disease who could not drive an automobile or dress himself unaided was linked to a burglary which had occurred 200 miles from his home. In spite of protestations of innocence and alibi evidence police arrested him because the DNA profiles matched and 'so it had to be him'. It was several months before10-point DNA tests were done on samples from the suspect and the crime scene. The results exonerated him.
He gained his freedom and a brief note from the prosecutor saying that charges were being dropped because ‘there was not enough evidence to provide a realistic chance of conviction’. He still awaits an official apology. Or even an admission of error.”
The reason why Mr. Easton was initially suspected was an adventitious match, as opposed to contamination. This case shows that adventitious matches can happen especially for partial profiles. The first profile had only six loci, but the second profile had 10 loci. As with DNA contamination, when a cold hit match leads to an absurd result, the DNA evidence needs to be reconsidered.
The Sylvester murder, a cold hit combined with a partial profile
According to Dr. Donald Riley, “A partial profile is one in which not all of the loci targeted show up in the sample. For example, if 13 loci were targeted, and only 9 could be reported, that would be termed, a partial profile…Over-interpretation of partial profiles can probably lead to serious mistakes. Such mistakes could include false inclusions and false exclusions, alike.” Let us examine the rape and murder of a young nurse which ultimately yielded a partial profile of the assailant many years later.
Diana Sylvester was raped and murdered in San Francisco in 1972. After evidence in this case was subjected to forensic DNA analysis, a trawl through California’s DNA database identified a suspect over thirty years later, a cold hit. Of the investigations treated here, the Sylvester murder is the one in which the particulars of the investigation (a cold hit) and the differences in expert opinion on the correct statistical calculation have the least relevance to the Knox/Sollecito case. However, several more subtle points in common can be found.
In this case the suspect was identified on the basis of his DNA matching a partial profile from evidence taken from the victim. This suspect, John Puckett was in the DNA database because of his convictions for rape about five years after Ms. Sylvester was raped and murdered. However, the MO of the crime was consistent with another rapist, Robert Baker, who matched the physical description of the assailant better than Mr. Puckett and who was deceased by the time the case was reopened. The defense was barred from introducing information about Mr. Baker, the original suspect. Over the objections of the defense, the prosecution was allowed to bring in Mr. Puckett’s past convictions. How strong was the DNA evidence against Mr. Puckett?
The main issue in this case is a disagreement among experts over the correct statistical calculation to use in cold hit cases. Another key element in this case is that it made use of a partial, not full, DNA profile. In the United States a full DNA profile has thirteen separate markers (loci). A profile must have seven markers for it to be searched in California’s database. However, only 5 and a half markers were clearly found in the Sylvester murder. The jury was told that the chances of a random person’s matching the DNA found at the crime scene were 1.1 million to one. Yet when the odds were calculated with a different set of statistical assumptions the odds were only one in three, a statistic that the jury was barred from hearing. This is why the odds were only 1.1 million to one, and not substantially higher. However, when one uses a model that takes into account that there were 338,000 profiles in the database, one arrives at the 1-in-3 odds. The question of which model is better is a difficult one, yet it is odd that California courts have taken it upon themselves to decide which model is more appropriate. And the difference between one in 1.1 million and 1 in 3 is huge. It would have probably been enough to move at least one juror from guilty to not guilty beyond a reasonable doubt.
A second issue concerns the number of loci in profile itself. The peaks that were needed to flesh out the profile from 5.5 loci to 8 loci fell below the laboratory’s intensity threshold, but forensic technician Bonnie Cheng wished to interpret them anyway. DNA profiles contain artifact peaks, some of which are known as blobs and others as stutters. Deciding which peaks are true and which are artifacts may contain an element of subjectivity. The prosecution’s outside DNA witness, Dr. Chakraborty used Mr. Puckett’s full profile to interpret the partial profile, a practice that is open to serious question.
A third issue is that the sample was mixed, containing DNA markers from both the victim and assailant. The question of which markers belong to which profiles naturally arises. DNA forensic expert Peter Gill said, “If you show 10 colleagues a mixture, you will probably end up with 10 different answers.” With reference to this case Dan Krane made an important point, “There is a public perception that DNA profiles are black and white. The reality is that easily in half of all cases—namely, those where the samples are mixed or degraded—there is the potential for subjectivity.”
A fourth issue is that the lab used up so much of the sample that the defense could not do its own testing. This is a debatable practice in a DNA case; some guidelines indicate that this should not be done unless the defense agrees in advance.
One lesson for students of the Knox/Sollecito case is that the judge’s decisions might control the outcome of a case. The judge’s decision to exclude one statistical model in the Puckett case can be compared with Judge Massei’s decision not to order an independent review of the forensics of the Knox/Sollecito case. A second message is that DNA profiling is not immune to cognitive bias. In both the Puckett case and the Knox/Sollecito case, the forensic technicians lowered the bar with respect to the intensity threshold. A third fact to bear in mind is that Meredith’s DNA profile from the kitchen knife was a partial profile. However, how many loci should be counted for this piece of evidence depends entirely upon one’s choice of intensity threshold. Fourth, the bra clasp is a mixed sample, and interpreting mixtures contains an element of subjectivity.
Some possible reforms
Australian criminal defense barrister Peter Faris wrote in response to the Benjamin Forbes case, “Faced with a figure of 10 billion, a jury will always convict. The only way that it can be defended is for the defence to demonstrate a doubt arising from contamination, forensic or statistical procedures. In the real world, defence lawyers and legal aid bodies are just not equipped to investigate these matters. Many cases rely (to a greater or lesser extent) on DNA evidence. In some of them, such as Forbes, there is simply no other evidence. Consequently, if there is contamination at the scene, in police or laboratory storage or in the laboratory itself, the defence can never prove it.
Mr. Faris proposed some reforms:
“DNA should never be admitted unless there is corroboration: that is, there must be some other evidence of the identity of the offender. As for the rest of DNA cases, the solution is to put the burden on the prosecution. This can be done by amending the various Evidence Acts around the country to make DNA evidence inadmissible unless the trial judge is first satisfied, by the prosecution, that it should be admitted. The prosecution should apply to the trial judge, in a preliminary hearing, to admit DNA evidence. They must satisfy the judge, on the balance of probabilities, of various matters. The important matters are that the burden of admissibility is upon the crown. No DNA evidence could be led unless this procedure has been completed.
Conditions could be imposed in the legislation to protect the accused. For example, the prosecution would be required to produce evidence to disprove contamination, whether at the scene or in the laboratory. Strict proof of continuity of exhibits would be required. The prosecution would have to call evidence of the current international statistical procedures. Proof by the defence of international articles and learned writings could be relaxed.”
Final Thoughts
We have examined the problems with clerical errors, contamination, statistical manipulation, and outright fraud in this and preceding posts. It must also be borne in mind that the presence of DNA on an object rarely provides information on the time or means (primary, secondary, etc.) of its deposition. Paradoxically, DNA profiling is the branch of forensics with the firmest grounding in science. Much evidence exists to the effect that it is held in particularly high esteem by juries (a possible subject for a future post).
Taking all of these issues into account, I would not convict someone in a case where the sole piece of evidence comes from DNA forensics, but I would give it considerable weight, provided that the data were obtained legitimately and presented to the court in a transparent manner that respected the discovery rights of the defense. The worthy question of whether or not states should demand DNA samples upon felony arrest is outside the scope of this post.
This post returns to the problem of forensic DNA contamination. It also addresses the problem of partial profiles and adventitious matches, especially with respect to cold cases. North Carolinians might want to take special note of the John Puckett and Raymond Easton cases, inasmuch as North Carolina may join other states in demanding DNA samples upon arrest. My prediction is that as the size of a DNA database grows, we will see a greater number of cold case convictions that turn out to be erroneous.
Murder of Jane Mixer
We have previously encountered the conviction of Gary Leiterman of the murder of Jane Mixer. The presence of both Mr. Leiterman’s DNA and that of John Ruelas. The prosecution was unable to come up with a reasonable explanation for Mr. Ruelas’ DNA; he was four years old at the time and lived in another city.
Dr. Theodore Kessis reexamined the DNA forensics of this case:
“Review of the electropherograms associated with this negative control sample (NEG 041902) reveals that it was contaminated, a fact that cannot be disputed since Dr. Milligan himself labeled it with a note indicating as much (Appendix 8 - Electropherogram sample NEG 041902).
Remarkably, Dr. Milligan stated in his 7/15/02 testimony that no contamination events had occurred during the course of his testing and that if any had, he would have documented them in his reports (pg. 141-21 and 142-4). Equally difficult to rectify here is the fact that when asked if he had ever committed an error, Dr. Milligan's replied he could never recall making one. (pg. 162, lines 1-5)”
While agreeing with others that most contamination events happen when two samples are handled closely in space and time, Dr. Kessis also offered a caution, “It must be noted however that contamination errors have been documented where no direct processing link between sample and contaminant have been established, raising the specter that a source of contamination can linger in a laboratory for some time.”
Dr. Kessis found another deficiency: “As previously mentioned, Corrective Action files and Error logs form an important part of a laboratory's quality control and assurance programs by centralizing the documentation of errors within the laboratory. Mandated by the DAB Standards (Appendix 2, section 14.1.1), such data allows laboratory management to quickly and efficiently identify and address systematic problems that affect the reliability of testing results.”
“Given the thousands of samples, hundreds of cases, and number of people handling casework within this laboratory, the lack of a centralize system to track errors and discrepancy indicates that the lab had no mechanism in place to identify and deal with systematic problems such as contamination events.”
There are several take-home messages for students of the Knox/Sollecito case here. Contamination by more than one individual’s DNA is possible. The laboratories in question will sometimes claim to be error-free, as did the Rome lab. In such an instance it would be helpful to check the laboratory’s corrective action files, which are more likely to be accurate than someone’s memory. Whether the Rome lab has such files is unclear. Finally, when DNA results force one to an absurd conclusion (as with the kitchen knife), contamination or misinterpretation should be suspected.
The case of Gregory Turner
Gregory Turner was indicted and jailed for a murder when the DNA from a murdered woman in Newfoundland was found on his wedding ring. The ring also contained DNA from one other contributor, thought to be his accomplice. However, the lawyer sought out the names of the technicians from the lab and determined that the technician working on his ring also worked on the victim’s fingernails. Moreover, the DNA from the second contributor to the ring turned out to be the profile of the technician herself. After many months, Mr. Turner was released from jail. This particular case of DNA contamination is an example of where both primary and secondary transfer of DNA occurred. As did the Mixer case, it shows that contamination can transfer the DNA from more than one person onto an item of evidence. This is worth bearing in mind given the multiple DNA contributors to the bra clasp in the Knox/Sollecito case.
Profile N
As was true in the Jaidyn Leskie case, the victim of one crime can become a suspect in other crimes on the basis of contaminated DNA evidence. Sometimes it takes a major foul-up to prod a laboratory into corrective action. In New Zealand, the Wellington police were investigating two murders, dubbed Rex and Pad, as well as N, the victim of an assault.
Michael Strutt reported, “One caught up in the testing was a mild mannered Christchurch man who had been assaulted outside his local, the Hagley Arms Hotel, on 23 April 1998. Police had taken blood in order to eliminate his DNA from samples taken from the scene of the assault and sent it to ESR for testing. The result of this test came to be dubbed 'Profile N' by the inquiries which were to follow… The Christchurch assault victim was subjected to 'extensive police inquiries' for more than three months and his financial records were seized. This established what he had claimed all along, that he had not left Christchurch around the time of the murders. In fact he hardly left Christchurch at all… Although they never discovered exactly how the mistakes had happened they did determine that the 'Rex' and 'Pad' samples had been accidentally contaminated with DNA from Profile N at an early stage of processing at ESR's Mt Albert laboratories. Extracts from them sent to other laboratories for testing also returned Profile N. Numerous recommendations for improving oversight, record keeping and even laboratory ventilation were made.”
“During the inquiry ESR [Environmental Science & Research Ltd] was asked to check the results of all testing done in July 1998 for any further instances of Profile N. Although they initially reported that none were found, later retests showed a partial profile consistent with N in another sample from 'Pad'. They also revealed 25 other 'unexplained' profiles in 14 of the 36 samples tested that month.”
A group investigating these cases asked a manager of the forensic unit of the ESR lab to comment, “The Wellington murders you refer to were not DNA failures. The problem was picked up and investigated. Five separate investigations failed to find scientific proof for the cause of the anomalies. No direct evidence of either accidental or deliberate contamination has come to light. Existing facilities and protocols were shown to meet independent quality audit requirements. The Ministerial Inquiry recognising the points above concluded that on the balance of probabilities the apparently anomalous results could be ascribed to accidental contamination of DNA extracts within the ESR laboratory. They made a number of recommendations which ESR has either implemented or is planning to implement. This sits comfortably with our continuous improvement management focus.”
The fact that the lab in question met the audit requirements is evidence that simply following accepted protocols does not guarantee that contamination will never happen. The lack of the determination of an exact mechanism of contamination is consistent with Dr. Kessis’s caution in the Mixer case above. People who argue that Amanda Knox and Raffaele Sollecito are guilty sometimes demand a mechanism of contamination; unfortunately, this cannot always be determined.
The first false cold hit case in the UK
Michael Strutt wrote, “A man [Raymond Easton] with advanced Parkinsons disease who could not drive an automobile or dress himself unaided was linked to a burglary which had occurred 200 miles from his home. In spite of protestations of innocence and alibi evidence police arrested him because the DNA profiles matched and 'so it had to be him'. It was several months before10-point DNA tests were done on samples from the suspect and the crime scene. The results exonerated him.
He gained his freedom and a brief note from the prosecutor saying that charges were being dropped because ‘there was not enough evidence to provide a realistic chance of conviction’. He still awaits an official apology. Or even an admission of error.”
The reason why Mr. Easton was initially suspected was an adventitious match, as opposed to contamination. This case shows that adventitious matches can happen especially for partial profiles. The first profile had only six loci, but the second profile had 10 loci. As with DNA contamination, when a cold hit match leads to an absurd result, the DNA evidence needs to be reconsidered.
The Sylvester murder, a cold hit combined with a partial profile
According to Dr. Donald Riley, “A partial profile is one in which not all of the loci targeted show up in the sample. For example, if 13 loci were targeted, and only 9 could be reported, that would be termed, a partial profile…Over-interpretation of partial profiles can probably lead to serious mistakes. Such mistakes could include false inclusions and false exclusions, alike.” Let us examine the rape and murder of a young nurse which ultimately yielded a partial profile of the assailant many years later.
Diana Sylvester was raped and murdered in San Francisco in 1972. After evidence in this case was subjected to forensic DNA analysis, a trawl through California’s DNA database identified a suspect over thirty years later, a cold hit. Of the investigations treated here, the Sylvester murder is the one in which the particulars of the investigation (a cold hit) and the differences in expert opinion on the correct statistical calculation have the least relevance to the Knox/Sollecito case. However, several more subtle points in common can be found.
In this case the suspect was identified on the basis of his DNA matching a partial profile from evidence taken from the victim. This suspect, John Puckett was in the DNA database because of his convictions for rape about five years after Ms. Sylvester was raped and murdered. However, the MO of the crime was consistent with another rapist, Robert Baker, who matched the physical description of the assailant better than Mr. Puckett and who was deceased by the time the case was reopened. The defense was barred from introducing information about Mr. Baker, the original suspect. Over the objections of the defense, the prosecution was allowed to bring in Mr. Puckett’s past convictions. How strong was the DNA evidence against Mr. Puckett?
The main issue in this case is a disagreement among experts over the correct statistical calculation to use in cold hit cases. Another key element in this case is that it made use of a partial, not full, DNA profile. In the United States a full DNA profile has thirteen separate markers (loci). A profile must have seven markers for it to be searched in California’s database. However, only 5 and a half markers were clearly found in the Sylvester murder. The jury was told that the chances of a random person’s matching the DNA found at the crime scene were 1.1 million to one. Yet when the odds were calculated with a different set of statistical assumptions the odds were only one in three, a statistic that the jury was barred from hearing. This is why the odds were only 1.1 million to one, and not substantially higher. However, when one uses a model that takes into account that there were 338,000 profiles in the database, one arrives at the 1-in-3 odds. The question of which model is better is a difficult one, yet it is odd that California courts have taken it upon themselves to decide which model is more appropriate. And the difference between one in 1.1 million and 1 in 3 is huge. It would have probably been enough to move at least one juror from guilty to not guilty beyond a reasonable doubt.
A second issue concerns the number of loci in profile itself. The peaks that were needed to flesh out the profile from 5.5 loci to 8 loci fell below the laboratory’s intensity threshold, but forensic technician Bonnie Cheng wished to interpret them anyway. DNA profiles contain artifact peaks, some of which are known as blobs and others as stutters. Deciding which peaks are true and which are artifacts may contain an element of subjectivity. The prosecution’s outside DNA witness, Dr. Chakraborty used Mr. Puckett’s full profile to interpret the partial profile, a practice that is open to serious question.
A third issue is that the sample was mixed, containing DNA markers from both the victim and assailant. The question of which markers belong to which profiles naturally arises. DNA forensic expert Peter Gill said, “If you show 10 colleagues a mixture, you will probably end up with 10 different answers.” With reference to this case Dan Krane made an important point, “There is a public perception that DNA profiles are black and white. The reality is that easily in half of all cases—namely, those where the samples are mixed or degraded—there is the potential for subjectivity.”
A fourth issue is that the lab used up so much of the sample that the defense could not do its own testing. This is a debatable practice in a DNA case; some guidelines indicate that this should not be done unless the defense agrees in advance.
One lesson for students of the Knox/Sollecito case is that the judge’s decisions might control the outcome of a case. The judge’s decision to exclude one statistical model in the Puckett case can be compared with Judge Massei’s decision not to order an independent review of the forensics of the Knox/Sollecito case. A second message is that DNA profiling is not immune to cognitive bias. In both the Puckett case and the Knox/Sollecito case, the forensic technicians lowered the bar with respect to the intensity threshold. A third fact to bear in mind is that Meredith’s DNA profile from the kitchen knife was a partial profile. However, how many loci should be counted for this piece of evidence depends entirely upon one’s choice of intensity threshold. Fourth, the bra clasp is a mixed sample, and interpreting mixtures contains an element of subjectivity.
Some possible reforms
Australian criminal defense barrister Peter Faris wrote in response to the Benjamin Forbes case, “Faced with a figure of 10 billion, a jury will always convict. The only way that it can be defended is for the defence to demonstrate a doubt arising from contamination, forensic or statistical procedures. In the real world, defence lawyers and legal aid bodies are just not equipped to investigate these matters. Many cases rely (to a greater or lesser extent) on DNA evidence. In some of them, such as Forbes, there is simply no other evidence. Consequently, if there is contamination at the scene, in police or laboratory storage or in the laboratory itself, the defence can never prove it.
Mr. Faris proposed some reforms:
“DNA should never be admitted unless there is corroboration: that is, there must be some other evidence of the identity of the offender. As for the rest of DNA cases, the solution is to put the burden on the prosecution. This can be done by amending the various Evidence Acts around the country to make DNA evidence inadmissible unless the trial judge is first satisfied, by the prosecution, that it should be admitted. The prosecution should apply to the trial judge, in a preliminary hearing, to admit DNA evidence. They must satisfy the judge, on the balance of probabilities, of various matters. The important matters are that the burden of admissibility is upon the crown. No DNA evidence could be led unless this procedure has been completed.
Conditions could be imposed in the legislation to protect the accused. For example, the prosecution would be required to produce evidence to disprove contamination, whether at the scene or in the laboratory. Strict proof of continuity of exhibits would be required. The prosecution would have to call evidence of the current international statistical procedures. Proof by the defence of international articles and learned writings could be relaxed.”
Final Thoughts
We have examined the problems with clerical errors, contamination, statistical manipulation, and outright fraud in this and preceding posts. It must also be borne in mind that the presence of DNA on an object rarely provides information on the time or means (primary, secondary, etc.) of its deposition. Paradoxically, DNA profiling is the branch of forensics with the firmest grounding in science. Much evidence exists to the effect that it is held in particularly high esteem by juries (a possible subject for a future post).
Taking all of these issues into account, I would not convict someone in a case where the sole piece of evidence comes from DNA forensics, but I would give it considerable weight, provided that the data were obtained legitimately and presented to the court in a transparent manner that respected the discovery rights of the defense. The worthy question of whether or not states should demand DNA samples upon felony arrest is outside the scope of this post.
Wednesday, June 2, 2010
How does the Patricia Stallings case shed light on the murder of Meredith Kercher?
Part XVI in the Knox/Sollecito case
Patricia Stallings was convicted, then exonerated of poisoning her infant son Ryan with ethylene glycol, the major component of antifreeze. When Ryan was unable to keep food down, Mrs. Stallings took Ryan to Cardinal Glennon Children’s hospital accidentally, which happened to be associated with a toxicology unit. Ryan had metabolic acidosis (the pH of his blood was too low) and the laboratory associated with St. Louis University reported 180 milligrams per liter of ethylene glycol.
Ryan was put into foster care, but Mr. and Mrs. Stallings were allowed weekly visits. Four days after one such unsupervised visit, during which Mrs. Stallings gave Ryan a bottle, Ryan became ill again, having metabolic acidosis and died three days later. The same lab reported finding 911 milligrams per liter of ethylene glycol in Ryan’s serum and also in his baby bottle, which had been put into a dishwashing machine.
What are the odds of the tests being wrong?
There were three separate determinations of ethylene glycol, the original serum, the serum after the second feeding, and the bottle itself. In addition, one or both of the serum samples was also retested by a commercial lab. How could this be just chance? The prosecutor told the jury not to worry about motive, but just to concentrate on the fact that there was no rational explanation for these results except deliberate poisoning. He implied in so many words how unlikely it was for the labs to be wrong.
An alternative explanation begins to emerge
Patricia Stallings was arrested after a half-empty bottle of antifreeze was found in the couple’s basement. Mrs. Stallings was pregnant with her second son at the time of her arrest; her son David was immediately placed in foster care. David began to exhibit the same symptoms as Ryan, but he was taken to a children’s hospital. The hospital diagnosed David with a genetic disease known as methylmalonic acidemia (MMA)*. In this disease, one enzyme in a particular biological pathway is defective, causing a metabolic traffic jam, in which other compounds build up in the bloodstream. Although the odds of any one infant having this disease are about 1 in 48,000, David’s diagnosis meant that there was a one in four chance that Ryan had the disease as well. This fact was not allowed to be presented at her trial however, possibly because the judge and the defense attorney misunderstood each other with respect to what the defense attorney needed to do in order to bring the issue up.
Professor of biochemistry William Sly was one of the citizen-scientists who became involved in the case. Molecular geneticist Piero Rinaldo also reexamined the evidence, with some surprising results. James Shoemaker was involved in gathering evidence prior to the trial and subsequently. Both William Sly and Robert Ritter, Mrs. Stallings’ second attorney, learned of the case from the television show "Unsolved Mysteries.”
How could the analyses of ethylene glycol have been done better?
The gas chromatography (GC) technique measures how much time it takes for substances to pass through a column of stationary liquid (a waxlike substance) over which inert gas flows. This period is the retention time of a substance, and this length of time depends on its chemical properties. Two compounds may have the same retention time but usually do not.
The first analysis of ethylene glycol showed that the unknown compound in Ryan’s serum had a retention time within 30 seconds of a standard of ethylene glycol. A difference of 30 seconds is larger than is typically seen for an identical compound run twice, but let us assume generously that 30 seconds is within experimental error between one GC run and the next. The investigators should not have concluded that they had identified ethylene glycol even under this assumption, rather they should have performed additional tests.
One way to distinguish between two compounds that have identical or almost identical retention times is to run each compound through a mass spectrometer as it emerges from the end of the column. The mass spectrometer measures how heavy a compound is and in some cases how heavy the fragments of the compound are when the compound disintegrates. The combined technique gas chromatography-mass spectrometry (GC/MS) is usually very discriminating between one compound and the next, but it was just coming into widespread use about the time of the Stallings case in 1989.
A second way to distinguish two compounds is to run the gas chromatography experiment three times with three chemically distinct stationary phases. If the retention times of the two compounds, the unknown and the standard, are the same in all three trials, then the two compounds are probably identical. A third way is to spike a portion of the sample with the unknown compound with the reference. This eliminates the factors that cause run-to-run variation in retention times. The labs in question apparently did not do any of these three additional tests.
Shoemaker, Sly, and their coworkers examined a stored sample of Ryan’s blood using gas chromatography/mass spectrometry and showed that the substance believed to be ethylene glycol was actually propionic acid, one of the substances that would be expected to be elevated if Ryan had the same genetic disorder as his brother David. They also spiked a sample of Ryan’s blood with ethylene glycol and showed that it did not have the same retention time as the unknown compound, now identified as propionic acid.
The analysis of Ryan’s blood after the unsupervised visit suggested a very high concentration of ethylene glycol. Yet ethylene glycol is highly water-soluble and clears the body with a half-life of 3.0 hours. The half-life is the time it takes for the concentration of a substance to go from some value x to x/2. Therefore, Ryan would have had to consume 300 liters of ethylene glycol during his unsupervised visit to account for his blood plasma concentration four days later, an absurd volume.
Dr. Rinaldo found evidence of methylmalonic acid in Ryan’s serum. Along with propionic acid, methylmalonic acid would be expected to be in elevated concentrations in a person suffering from MMA. He also reexamined the GC data from the two labs. He found that the commercial lab saw an unknown compound in Ryan’s serum and merely assumed it was ethylene glycol without even running a standard.
He was unable to find evidence of ethylene glycol in the tests that were run on the bottle, but the bottle itself had gone missing. The positive result for ethylene glycol on the baby bottle should have raised a red flag on its own. Ethylene glycol in the bottle would have been washed and rinsed away in the dishwasher. Drs. Shoemaker and Sly believed that the small amounts of ethylene glycol found in some of the samples were due to contamination.
Cognitive bias
Once some of these facts emerged, D.A. McElroy joined with Mrs. Stallings’ new lawyer in a motion of ineffective counsel. First Mrs. Stallings was granted a new trial, and later the charges were dropped.
The first analysis to show ethylene glycol was done in a toxicology laboratory, and they might have been trained to focus on poisonings, not inherited metabolic disorders. Dr. Bob Smith called this an “expectation effect,” and he later referred to the general forensic phenomenon as “investigator bias.” The commercial lab that retested on of the serum samples may have been guilty of confirmation bias. It seems likely but not a certainty that the second lab knew that ethylene glycol poisoning was suspected. In this context it is interesting that Dr. Shoemaker later sent normal plasma spiked with propionic acid to three laboratories and two of the three reported finding ethylene glycol.
The lab that first identified the unknown compound might or might not have been following the standard protocols of the day, but the protocol was insufficiently rigorous in the sense that the identification was only one piece of information, the retention time, as discussed above. However, the commercial lab was deficient by any measure. Clearly, neither lab did a thorough job of examining all information pertaining to Ryan’s serum.
Roger Koppl discussed many of the problems that beset forensic science in the United States. Some of the problems he illuminates, such as dependency bias, were not factors in the Stallings case but may have been at work in the Knox/Sollecito case. He wrote, “the typical forensic worker has psychological incentives to reach findings based on his
close psychological ties with the law enforcement community he serves.” He also treated confirmation and other cognitive biases (p. 13).
“Larry S. Miller demonstrates an excellent example of cognitive bias at play. He asked a group of 14 students trained in hair analysis, all of whom met the basic requirements for expert testimony on human hair identification in courts of law, to examine four cases each. For each student, two cases were presented the usual way: They were given two samples and told that one was from the crime scene and the other from the suspect. The other two cases were presented through a forensic lineup. The known sample from the imaginary crime scene was compared to five suspect-known hair samples. In all 56 cases, there were in reality no true matches. The first group of cases yielded an error rate of 30.8 percent; the second group an error rate of only 3.8 percent.12
Miller’s study illustrates how evidence is often presented to the forensic scientist in a bias-inducing manner. The samples are labeled as coming from the defendant or from the victim and are frequently accompanied by a synopsis of the investigation indicating the reasons that the investigators believe the suspect is guilty. This protocol cues the forensic worker to the expected or correct result.”
The Stallings case in the context of the Knox/Sollecito case
The Johnson/Hampikian open letter criticized both the DNA evidence surrounding the knife and the bra clasp. Some observers of the Knox/Sollecito case have asked what are the odds that both of the DNA results could be the result of contamination or secondary transfer. One might ask what are the odds of at least four identifications of ethylene glycol being wrong, and yet they were in Stallings case. It may be that assigning a probability to the chances of both the bra clasp and the knife being the result of contamination or secondary transfer by standard rules is misleading. When two events are independent, the probability of both occurring are the product of the probabilities of each. So if event A has a 10% probability, and event B has a 10% probability, then the probability of both is 1%. However, when some form of cognitive bias is in play, then this calculation does not apply; in other words, the two events are no longer independent.
Some other parallels can be found. In both cases the investigators seemed oblivious to the contradictory nature of their findings. The second determination of ethylene glycol in Ryan’s serum was so high as to rule out ethylene glycol poisoning four days earlier. The lack of blood on the kitchen knife should have told the forensic DNA analysts that Meredith’s DNA profile was the result of contamination. In both cases the motive for the crime was dubious. Patricia Stallings was thought to be guilty of Munchausen’s by proxy syndrome on the basis of scant evidence. Amanda Knox was accused of trying to get back at Meredith Kercher, because of tensions from rooming together.
References
Michelle Hoffman, “Scientific Sleuths Solve a Murder Mystery,” (1991) Science 253, 931.
Roger Koppl, “CSI for Real: How to Improve Forensics Science”
Dr. Bob Mead, “Accused and Convicted—a case study”
Journal of Pediatrics, The. 1992 Mar;120(3):417-21. Misidentification of propionic acid as ethylene glycol in a patient with methylmalonic acidemia. Shoemaker JD, Lynch RE, Hoffmann JW, Sly WS.
Bill Smith, “Not Guity! How the system failed Patricia Stallings”
Appendix: Methylmalonic acidemia* (MMA)
A metabolic pathway is a series of chemical conversions, in which an enzyme catalyzes each reaction. Enzymes are the products of genes, and an alteration of a gene from its normal form may produce an enzyme that does not function properly. The compound propionyl coenzyme A is the thioester of propionic acid conjugated with coenzyme A (CoA), a thiol. When propionyl coenzyme A is produced in the body, it is converted into succinyl coenzyme A in a pathway that is three steps long: Propionyl CoA carboxylase is the enzyme that changes propionyl CoA into D-methylmalonyl CoA, and this compound is converted into L-methylmalonyl CoA by methylmalonyl CoA epimerase. Finally, this compound is converted into succinyl CoA by the vitamin B12-dependent enzyme methylmalonyl CoA mutase. The gene for this last enzyme is defective in methylmalonic academia, and the inheritance pattern is autosomal recessive. When this happens, the previous compounds build up in concentration. At some point the bond linking propionic acid or methylmalonic acid and coenzyme A is hydrolyed, and the free acids are found in the bloodstream. Among the symptoms of this disease are lethargy, seizures, and vomiting. Metabolic acidosis and ketosis are also observed. Some forms respond to supplementation with vitamin B12.
References to Appendix
Healthline
Nelson, DL and Cox, MM, "Lehninger Principles of Biochemistry," 5th edition.
*update 6/3/10, 4:30 PM. Corrected several spelling errors/typos.
Patricia Stallings was convicted, then exonerated of poisoning her infant son Ryan with ethylene glycol, the major component of antifreeze. When Ryan was unable to keep food down, Mrs. Stallings took Ryan to Cardinal Glennon Children’s hospital accidentally, which happened to be associated with a toxicology unit. Ryan had metabolic acidosis (the pH of his blood was too low) and the laboratory associated with St. Louis University reported 180 milligrams per liter of ethylene glycol.
Ryan was put into foster care, but Mr. and Mrs. Stallings were allowed weekly visits. Four days after one such unsupervised visit, during which Mrs. Stallings gave Ryan a bottle, Ryan became ill again, having metabolic acidosis and died three days later. The same lab reported finding 911 milligrams per liter of ethylene glycol in Ryan’s serum and also in his baby bottle, which had been put into a dishwashing machine.
What are the odds of the tests being wrong?
There were three separate determinations of ethylene glycol, the original serum, the serum after the second feeding, and the bottle itself. In addition, one or both of the serum samples was also retested by a commercial lab. How could this be just chance? The prosecutor told the jury not to worry about motive, but just to concentrate on the fact that there was no rational explanation for these results except deliberate poisoning. He implied in so many words how unlikely it was for the labs to be wrong.
An alternative explanation begins to emerge
Patricia Stallings was arrested after a half-empty bottle of antifreeze was found in the couple’s basement. Mrs. Stallings was pregnant with her second son at the time of her arrest; her son David was immediately placed in foster care. David began to exhibit the same symptoms as Ryan, but he was taken to a children’s hospital. The hospital diagnosed David with a genetic disease known as methylmalonic acidemia (MMA)*. In this disease, one enzyme in a particular biological pathway is defective, causing a metabolic traffic jam, in which other compounds build up in the bloodstream. Although the odds of any one infant having this disease are about 1 in 48,000, David’s diagnosis meant that there was a one in four chance that Ryan had the disease as well. This fact was not allowed to be presented at her trial however, possibly because the judge and the defense attorney misunderstood each other with respect to what the defense attorney needed to do in order to bring the issue up.
Professor of biochemistry William Sly was one of the citizen-scientists who became involved in the case. Molecular geneticist Piero Rinaldo also reexamined the evidence, with some surprising results. James Shoemaker was involved in gathering evidence prior to the trial and subsequently. Both William Sly and Robert Ritter, Mrs. Stallings’ second attorney, learned of the case from the television show "Unsolved Mysteries.”
How could the analyses of ethylene glycol have been done better?
The gas chromatography (GC) technique measures how much time it takes for substances to pass through a column of stationary liquid (a waxlike substance) over which inert gas flows. This period is the retention time of a substance, and this length of time depends on its chemical properties. Two compounds may have the same retention time but usually do not.
The first analysis of ethylene glycol showed that the unknown compound in Ryan’s serum had a retention time within 30 seconds of a standard of ethylene glycol. A difference of 30 seconds is larger than is typically seen for an identical compound run twice, but let us assume generously that 30 seconds is within experimental error between one GC run and the next. The investigators should not have concluded that they had identified ethylene glycol even under this assumption, rather they should have performed additional tests.
One way to distinguish between two compounds that have identical or almost identical retention times is to run each compound through a mass spectrometer as it emerges from the end of the column. The mass spectrometer measures how heavy a compound is and in some cases how heavy the fragments of the compound are when the compound disintegrates. The combined technique gas chromatography-mass spectrometry (GC/MS) is usually very discriminating between one compound and the next, but it was just coming into widespread use about the time of the Stallings case in 1989.
A second way to distinguish two compounds is to run the gas chromatography experiment three times with three chemically distinct stationary phases. If the retention times of the two compounds, the unknown and the standard, are the same in all three trials, then the two compounds are probably identical. A third way is to spike a portion of the sample with the unknown compound with the reference. This eliminates the factors that cause run-to-run variation in retention times. The labs in question apparently did not do any of these three additional tests.
Shoemaker, Sly, and their coworkers examined a stored sample of Ryan’s blood using gas chromatography/mass spectrometry and showed that the substance believed to be ethylene glycol was actually propionic acid, one of the substances that would be expected to be elevated if Ryan had the same genetic disorder as his brother David. They also spiked a sample of Ryan’s blood with ethylene glycol and showed that it did not have the same retention time as the unknown compound, now identified as propionic acid.
The analysis of Ryan’s blood after the unsupervised visit suggested a very high concentration of ethylene glycol. Yet ethylene glycol is highly water-soluble and clears the body with a half-life of 3.0 hours. The half-life is the time it takes for the concentration of a substance to go from some value x to x/2. Therefore, Ryan would have had to consume 300 liters of ethylene glycol during his unsupervised visit to account for his blood plasma concentration four days later, an absurd volume.
Dr. Rinaldo found evidence of methylmalonic acid in Ryan’s serum. Along with propionic acid, methylmalonic acid would be expected to be in elevated concentrations in a person suffering from MMA. He also reexamined the GC data from the two labs. He found that the commercial lab saw an unknown compound in Ryan’s serum and merely assumed it was ethylene glycol without even running a standard.
He was unable to find evidence of ethylene glycol in the tests that were run on the bottle, but the bottle itself had gone missing. The positive result for ethylene glycol on the baby bottle should have raised a red flag on its own. Ethylene glycol in the bottle would have been washed and rinsed away in the dishwasher. Drs. Shoemaker and Sly believed that the small amounts of ethylene glycol found in some of the samples were due to contamination.
Cognitive bias
Once some of these facts emerged, D.A. McElroy joined with Mrs. Stallings’ new lawyer in a motion of ineffective counsel. First Mrs. Stallings was granted a new trial, and later the charges were dropped.
The first analysis to show ethylene glycol was done in a toxicology laboratory, and they might have been trained to focus on poisonings, not inherited metabolic disorders. Dr. Bob Smith called this an “expectation effect,” and he later referred to the general forensic phenomenon as “investigator bias.” The commercial lab that retested on of the serum samples may have been guilty of confirmation bias. It seems likely but not a certainty that the second lab knew that ethylene glycol poisoning was suspected. In this context it is interesting that Dr. Shoemaker later sent normal plasma spiked with propionic acid to three laboratories and two of the three reported finding ethylene glycol.
The lab that first identified the unknown compound might or might not have been following the standard protocols of the day, but the protocol was insufficiently rigorous in the sense that the identification was only one piece of information, the retention time, as discussed above. However, the commercial lab was deficient by any measure. Clearly, neither lab did a thorough job of examining all information pertaining to Ryan’s serum.
Roger Koppl discussed many of the problems that beset forensic science in the United States. Some of the problems he illuminates, such as dependency bias, were not factors in the Stallings case but may have been at work in the Knox/Sollecito case. He wrote, “the typical forensic worker has psychological incentives to reach findings based on his
close psychological ties with the law enforcement community he serves.” He also treated confirmation and other cognitive biases (p. 13).
“Larry S. Miller demonstrates an excellent example of cognitive bias at play. He asked a group of 14 students trained in hair analysis, all of whom met the basic requirements for expert testimony on human hair identification in courts of law, to examine four cases each. For each student, two cases were presented the usual way: They were given two samples and told that one was from the crime scene and the other from the suspect. The other two cases were presented through a forensic lineup. The known sample from the imaginary crime scene was compared to five suspect-known hair samples. In all 56 cases, there were in reality no true matches. The first group of cases yielded an error rate of 30.8 percent; the second group an error rate of only 3.8 percent.12
Miller’s study illustrates how evidence is often presented to the forensic scientist in a bias-inducing manner. The samples are labeled as coming from the defendant or from the victim and are frequently accompanied by a synopsis of the investigation indicating the reasons that the investigators believe the suspect is guilty. This protocol cues the forensic worker to the expected or correct result.”
The Stallings case in the context of the Knox/Sollecito case
The Johnson/Hampikian open letter criticized both the DNA evidence surrounding the knife and the bra clasp. Some observers of the Knox/Sollecito case have asked what are the odds that both of the DNA results could be the result of contamination or secondary transfer. One might ask what are the odds of at least four identifications of ethylene glycol being wrong, and yet they were in Stallings case. It may be that assigning a probability to the chances of both the bra clasp and the knife being the result of contamination or secondary transfer by standard rules is misleading. When two events are independent, the probability of both occurring are the product of the probabilities of each. So if event A has a 10% probability, and event B has a 10% probability, then the probability of both is 1%. However, when some form of cognitive bias is in play, then this calculation does not apply; in other words, the two events are no longer independent.
Some other parallels can be found. In both cases the investigators seemed oblivious to the contradictory nature of their findings. The second determination of ethylene glycol in Ryan’s serum was so high as to rule out ethylene glycol poisoning four days earlier. The lack of blood on the kitchen knife should have told the forensic DNA analysts that Meredith’s DNA profile was the result of contamination. In both cases the motive for the crime was dubious. Patricia Stallings was thought to be guilty of Munchausen’s by proxy syndrome on the basis of scant evidence. Amanda Knox was accused of trying to get back at Meredith Kercher, because of tensions from rooming together.
References
Michelle Hoffman, “Scientific Sleuths Solve a Murder Mystery,” (1991) Science 253, 931.
Roger Koppl, “CSI for Real: How to Improve Forensics Science”
Dr. Bob Mead, “Accused and Convicted—a case study”
Journal of Pediatrics, The. 1992 Mar;120(3):417-21. Misidentification of propionic acid as ethylene glycol in a patient with methylmalonic acidemia. Shoemaker JD, Lynch RE, Hoffmann JW, Sly WS.
Bill Smith, “Not Guity! How the system failed Patricia Stallings”
Appendix: Methylmalonic acidemia* (MMA)
A metabolic pathway is a series of chemical conversions, in which an enzyme catalyzes each reaction. Enzymes are the products of genes, and an alteration of a gene from its normal form may produce an enzyme that does not function properly. The compound propionyl coenzyme A is the thioester of propionic acid conjugated with coenzyme A (CoA), a thiol. When propionyl coenzyme A is produced in the body, it is converted into succinyl coenzyme A in a pathway that is three steps long: Propionyl CoA carboxylase is the enzyme that changes propionyl CoA into D-methylmalonyl CoA, and this compound is converted into L-methylmalonyl CoA by methylmalonyl CoA epimerase. Finally, this compound is converted into succinyl CoA by the vitamin B12-dependent enzyme methylmalonyl CoA mutase. The gene for this last enzyme is defective in methylmalonic academia, and the inheritance pattern is autosomal recessive. When this happens, the previous compounds build up in concentration. At some point the bond linking propionic acid or methylmalonic acid and coenzyme A is hydrolyed, and the free acids are found in the bloodstream. Among the symptoms of this disease are lethargy, seizures, and vomiting. Metabolic acidosis and ketosis are also observed. Some forms respond to supplementation with vitamin B12.
References to Appendix
Healthline
Nelson, DL and Cox, MM, "Lehninger Principles of Biochemistry," 5th edition.
*update 6/3/10, 4:30 PM. Corrected several spelling errors/typos.
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