Tuesday, December 2, 2014

Gary Leiterman and DNA contamination


Jane Mixer was initially thought to be the victim of a possible serial killer, John Norman Collins.  Jane Mixer was murdered in 1969 near Ann Arbor, MI, but the DNA testing was done until 2002, a gap of approximately 33 years.  One item of evidence from the Mixer case showed DNA from John Ruelas, and several locations (on some panty hose and a towel) showed DNA from Gary Leiterman.  Despite the fact that the state had no other evidence against Leiterman, he was convicted of her murder in 2005.  John Ruelas was never charged.

A drop of blood from Mixer’s hand was preserved, and DNA from John Ruelas was found.  The prosecutor believed that the blood was from John Ruelas, but he did not offer a satisfactory explanation of how his blood came to be there.  Because Ruelas was four years old at the time of the murder and lived about forty miles away, the possibility that his DNA arrived instead via contamination must be considered.  As defense expert witness Theodore Kessis wrote, “The unexpected and never accounted for finding of John Ruelas’ profile on evidence in the Mixer case clearly demonstrates the proposition that contamination can and does occur between samples from different cases.”

The presence of Ruelas’ DNA is most easily explained by the fact that samples from John Ruelas were also processed in the crime laboratory of the State Police of Michigan contemporaneously with the samples from the Mixer murder.  But can the absence of Mixer’s DNA in the blood drop also be explained?  In 2004 C. Peel and P. Gill (“Attribution of DNA profiles to body fluid stains,” International Congress Series 1261, pp. 53-55) performed a series of experiments, in which a good DNA shedder handled the substrate (cotton or glass) for a blood stain, either before or after the blood from a different individual was placed on the substrate.  The blood was either diluted or the stain had been left to sit for some months, allowing for possible DNA degradation over time.  They used leucomalachite green as a presumptive test for blood.  Peel and Gill wrote, “…the more dilute or degraded the stain, the higher the contribution of the substrate handler’s DNA to the resulting profile.  A positive presumptive test could be obtained from samples when a profile originating from the body fluid was no longer detectable.”  Although it is tempting to associate the DNA that one finds in a stain to that stain, such an association is occasionally in error.  In some cases substrate controls can be helpful in determining whether or not DNA is associated with a particular stain.

It is essentially 100% certain that Ruelas’s DNA arrived on the items from the Mixer case via contamination, although the exact route is unclear.   Gary Leiterman’s DNA was also in the laboratory at that time.  No body fluid could be associated with Leiterman’s DNA associated with evidence from the Mixer case.  Sub-source DNA such as this is weaker in probative value than DNA associated with a particular tissue or body fluid.  Taking these facts and ideas into consideration, Leiterman’s DNA probably also arrived via contamination. 

A second line of evidence also implies that contamination is the most likely explanation.  A lab worker performed a negative control experiment during the time that a sample from the panty hose was being tested.  The negative controls will only show the presence of DNA in an electropherogram if DNA has been introduced unexpectedly into the experiment.  Theodore Kessis wrote, “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 indicated 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 reporters (p. 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 that he could never recall making one.”  CBS News reported that, “Lab supervisor Jeffrey Nye says he retraced every step and he does not believe there is any issue of contamination. ‘No issue whatsoever,’ he says.”  This is an astonishing statement.

This lack of disclosure of a contamination event and a similar occurrence in the Adam Scott case (Peter Gill, Misleading DNA Evidence, Academic Press, 2014, p. 22) demonstrates that one cannot implicitly rely upon a laboratory to report accurately the results of negative control reactions.  Yet this is valuable information; a jury might choose to discount testimony from a lab if it knew contamination had happened.  It is also worth recalling what William Thompson noted in “Tarnish on the Gold Standard,” which is that the some laboratory workers tamper with negative controls in various ways.  For these reasons full disclosure of the negative controls in the form of raw (meaning unprocessed) data is the best course of action for a judicial system.  Students of the Knox/Sollecito case will not be surprised to learn that the position of the Michigan State Police crime laboratory was foursquare against disclosure of the raw data.  Professor Thompson wrote, “The Deputy Director of the Michigan State Police issued a statement on May 12, 2005 opposing ‘the allowance of releasing raw electronic data for subsequent manipulations using software and parameters not validated by the Michigan State Police Forensic Laboratory’ and declaring that ‘it is the position of the Michigan State Police Forensic Science Division that any release of this (sic) data for processing with non-validated parameters is tantamount to evidence tampering.’”26  This is a self-evidently nonsensical position, and it also forces one to ask why the processing parameters chosen by a forensic laboratory are necessarily the optimal ones.

Conclusions
The DNA evidence against Gary Leiterman is compromised so completely by the presence of the DNA from John Ruelas that it scarcely should be called evidence at all.  Exactly how their DNA came to be on items of evidence from the murder of Jane Mixer is not known.  Dr. Theodore Kessis commented on the Benjamin LaGuer case:  “It is highly improbable that any given forensic DNA laboratory will take it upon itself to contact its accrediting bodies or the press and state for the record how often they make mistakes… To best understand the weaknesses associated with DNA testing we must rely upon the empirical, the occasions in which such deficiencies are revealed either by the press or internal review of a lab’s documentation of such problems by a defense expert.  A close look at either reveals that indeed many instances of DNA testing errors have lead to the false conviction of individuals.”  Regrettably, even the sworn testimony of laboratory personnel may be seriously in error, as in the Leiterman case.  Nor can a jury be counted upon to accurately weigh the odds of contamination.    Quite the contrary, juries sometimes discount alibi evidence, such as the Farah Jama case, or the fact that the defendant lived in one city and claimed never having been to the city where the crime occurred, as happened in the Adam Scott case.  Both cases are now generally believed to be instances of DNA contamination.

17 comments:

Chris Halkides said...

I now refer to John Norman Collins as a possible serial killer, as opposed to a serial killer. He was convicted of killing Karen Sue Beineman, and he is suspected of killing others.

Chris Halkides said...

I added first initials to Peel and Gill. I included year and publisher of the book Misleading DNA Evidence. I changed the word cases to instances in the last sentence.

Unknown said...

I remember seeing the Investigation Discovery program on this case. Obviously, the whole trial was not shown in a sixty minute program, but while the Ruelas DNA was mentioned as being present and contamination was possible (though denied by the prosecutor). I did not hear the additional information regarding Ruelas being charged with a crime and evidence from that crime being processed in the same lab where the Mixer murder evidence was processed. Throw in the facts that Leiterman's evidence from his arrest for a prescription drug offense AND that Jane Mixer's own samples showed severe degradation, while DNA found from Leiterman and Ruelas showed no such degradation...the odds of this being something other than contamination must be astronomical. Why is Mr. Leiterman still in prison...

Chris Halkides said...

Ruelas was only four years old at the time that Mixer was murdered, and was not charged with anything regarding her murder. His DNA was tested because he had murdered someone as an adult. The prosecutor's notion that he had a nosebleed at the scene of the crime is risible. I recall some time ago trying to track down exactly when Ruelas's and Leiterman's reference samples were in the lab. My recollection is that with Ruelas it was clear that his sample was exactly contemporaneous with the items from the Mixer murder. However, I had a slightly harder time nailing down Leiterman's sample. It is also noteworthy that the lab had indeed experienced contamination, yet they denied it at the trial. This points out a weakness of the American system, which is that the jury's verdict is treated as near sacrosanct.

Anonymous said...

Erin Murphy wrote, "Leiterman's sample came into the laboratory on February 22, 2002; the evidence in Ruelas's case was processed the day before. Leiterman's sample was first analyzed between July 17 and July 23; Ruelas's reference sample was submitted on July 19 then sent to an outside lab for testing. The Mixer evidence was processed at the lab between March 26, 2002, and April 9, 2002." p. 57, "Inside the Cell: The Dark Side of DNA"

Anonymous said...

Hard to sympathize with someone who drugged a foreign exchange student who was living with his family, then posed her (in the exact same pose that Jane Mixer was placed in by her murderer) and took pictures of her.

He also bragged that, with his access to pharmaceuticals, he could assault any woman he wanted to.

He can rot.

Chris Halkides said...

I agree that Leiterman's actions don't engender sympathy. One news report stated that, "The images showed the girl - drugged unconscious - lying on Leiterman's bed with her clothing pulled back to expose her genitals. Authorities said the pose was an eerie echo of Jane Mixer's corpse." Another one stated that, "Police noted that the positioning of the clothing was similar to the way Mixer was found. The girl told investigators she did not remember taking the photos." Based on just these two reports, I would say that you are overstating your case: "exact same" is a stronger claim than "similar." With Ruelas' DNA there can be no doubt that there was contamination. Given this evidence, what are your grounds for ruling out that Leiterman's DNA arrived in the same way? The prosecutor's claim that it was Ruelas' blood is a good example of the association fallacy, as Peter Gill has called it.

Dead by Dewani said...

As you said, Anonymous, Gary Leiterman can rot. The fact that the do-gooders can not find anyone more worthy of being their posterboys than the Leitermans and Steven Averys of the world underscores the hypocrisy of the innocence industry. Most they shill for are actually guilty. The few that aren't guilty of the specific crime they're charged with are often guilty of other heinous acts and aren't worthy of attention.

The number of actually and morally innocent people wrongfully convicted of crime is close to zero. The number of fraudulent claims of innocence epidemic.

Chris Halkides said...

lane99,

You wrote, "The few that aren't guilty of the specific crime they're charged with are often guilty of other heinous acts and aren't worthy of attention." A person is put on trial for committing a particular act, not something else he or she might have done. When the authorities reason as you have, it can get innocent people convicted, because it becomes that much easier to justify lazy, sloppy, or biased investigations. Which makes more sense, that Letterman murdered her and Ruelas had a nosebleed at the crime scene, or that John Norman Collins committed the crime?

Chris Halkides said...

lane99,

You wrote, "The number of actually and morally innocent people wrongfully convicted of crime is close to zero. The number of fraudulent claims of innocence epidemic." This is the sort of magical thinking I might associate with Judge Learned Hand. Let us imagine that a jury perceives beyond a reasonable doubt to mean at least 90% certain of guilt. That means that if they have 0-10% belief in innocence they will convict. If one is 90% percent certain, it means that one expects to be wrong 10% of the time, and so forth. In a 2014 paper in PNAS, Samuel Gross and colleagues estimated the wrongful conviction rate at 4% and argue that this is a conservative estimate of the false conviction rate.

Chris Halkides said...

The right question to ask with respect to Gary Letterman and Steven Avery is not whether or not they are nice people, but instead whether or not wrongfully convicted. The pertinent question with respect to this blog is to ask whether or not their convictions were based on false or misleading DNA evidence. I have given my reasons with respect to Mr. Leiterman. With respect to Mr. Avery there are at least two potential problems with the DNA evidence against him. One is that DNA that is recovered from a bullet should ordinarily be degraded by heat. Two is that the technician contaminated the negative control with her own DNA. The entire batch of runs should have been thrown out; not doing so is dubious from the point of view of professional ethics.

Dead by Dewani said...

Samuel Gross includes in his 4% "wrongfully convicted" many who actually committed the crimes they were convicted of. He's a shyster, as are you.

Unknown said...

Unlike Justice Scalia, Professor Gross did not use patently ridiculous reasoning. Can you you back up your claim about Professor Gross's statistic? Can you answer my question about Leiterman versus Collins? Can you back up your assertion that the number of innocent people in prison is close to zero? With respect to Mr. Avery, can you offer a logical argument as to when it is OK to ignore one's own control experiments? If not, maybe you would be happier commenting elsewhere.

Dead by Dewani said...

That "Professor Gross"' statistics are bogus is self-evident and contained in the small print of his methodology.

And you may not find it "patently ridiculous" to trumpet that people who actually committed the crimes they were convicted of can nonetheless be "exonerated" of them, but I would think most without an axe to grind would beg to differ.

Bye.

Unknown said...

lane99,

One, words to the effect that it is in the fine print but not identifying the particular fine print is not an answer to the question of what may be wrong with Professor Gross's methodology. Two, I have no financial incentive to claim someone is innocent or guilty. My only interest is the same one as everyone else's, namely to see that guilty people go to prison and innocent ones do not. Three, consider the following hypothetical: John Doe commits a crime but leaves no evidence. The police manufacture evidence to secure a conviction, but their actions are later uncovered and John Doe is exonerated. IMO the conviction was on false grounds, and including it in a statistic on false convictions is the correct thing to do.

However, I don't believe that the John Doe scenario happens very frequently. Can you provide an example of it? On the other hand scenarios in which the police or investigating teams suspect the wrong person and twist or manufacture the evidence to convict him or her are known. With respect to twisting there is Lindy Chamberlain or Greg Taylor, just off the top of my head. With respect to manufacturing that might apply to Steven Avery. I suspect that the serology in the Lloyd Eldon Miller case was manufactured, but it is difficult to be certain.

Unknown said...

The error rate of 0.027% was suggested by Joshua Marquis in a 2006 Op Ed for the New York Times, and the number was picked up by Justice Scalia. A fundamental problem with with this statistic is that it looks at DNA-based exonerations and compares them to all crimes, the vast majority of which do not involve DNA evidence. Whether or not this is patently ridiculous is up to each of us to determine.

Chris Halkides said...

lane99,

You are welcome to continue commenting here as long as you attack the arguments and not the arguer. Although Samuel Gross's PNAS article was not the subject of this post, it has come up in the comments, and I see no reason to curtail this discussion.