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Lack of Academic Research in U.S. on Secondary DNA Transfer Affects Criminal Defendants

by Steve Horn

The ivory tower of academia. It’s seemingly quite a long distance from the real-world implications of the U.S. criminal justice system’s often brutal iron fist. 

It’s a place in which professors and their assistants have the world at their fingertips for research. A collegial atmosphere for scholarly collaboration imbues the academy and knowledge-hungry students, helping to foster an enriching learning environment. And yet, despite these dynamics, in one particular research area, curiosity wanes within American universities. 

That is, in the area of secondary DNA transfer. Although it’s an area that has become increasingly prominent in trial and appellate court litigation and seen an entire scholarly book —Misleading DNA Evidence: Reasons for Miscarriages of Justice by Peter Gill — dedicated to the topic in 2014, a Criminal Legal News investigation has discovered a relative silence in this arena within academia. Indeed, CLN could only find a single lab in the U.S. that has published a significant piece of scholarship on the topic. 

Secondary DNA transfer, simply put, amounts to trace elements of DNA passed on through various means that can — in the eyes of prosecutors — sometimes place someone at a crime scene for an act he or she may never have committed (See: CLN, Sept. 2018, p. 1). That can mean passive transfer, from touching a surface at some point in time, or even touching someone else who then transfers that DNA to a surface in question. 

Put another way, DNA research techniques have become so sophisticated that they can now trace an individual to a locale with just a few skin cells. But just because the scientific technology has come a long way, it does not mean that when it gets applied by prosecutors that it cannot become junk science. The legal arena has lagged behind the reality of the science.

“DNA is everywhere in the environment. It can be transferred passively, e.g. by touching a surface, or actively, e.g. by secondary transfer, mediated by a person other than the defendant,” wrote Peter Gill, a researcher in the Department of Forensic Genetics at the University of Oslo Hospital in Norway in a 2012 academic journal article. “DNA will persist indefinitely in a dry environment, hence there is no implicit information attached to the DNA profile that gives a clue to the ‘how’ and ‘when’ transfer occurred.”

In light of the phenomenon of secondary DNA transfer, there is a grave risk of getting it wrong by jumping to conclusions based solely on the fact a particular DNA profile is found at a crime scene. Could defendants be wrongfully convicted via a false-positive gained from secondary-transfer DNA? And what are precautions police and prosecutors can take to avoid such a miscarriage of justice from occurring? 

On that note, U.S. academic researchers are nearly, but not wholly, silent. And that in itself is troubling. But though American academia has, for whatever reason, apparently been uninterested in investigating secondary DNA transfer, scholars abroad have done so, with important implications based on their findings. 

Uniformly, those researchers point to secondary DNA transfer as something that exists and to be wary of when it comes to making decisions about whether or not to lock someone up in prison for years, if not for life. To them, DNA does not deserve its gold-standard smoking-gun status but rather should be treated as a piece of evidence to be viewed with as much skepticism as any other within the adversarial legal system. 

Academia, of course, is not the U.S. criminal justice system or its system of jurisprudence. And just because U.S. scholars have avoided this niche, yet extremely consequential, subtopic with a 10-foot pole, one could argue, does not mean it doesn’t directly impact the courts. 

But scholarly work, while far from the main precedents judges rely upon to make decisions, is often cited in key cases of precedential importance in both state and federal courts. More importantly, the work academics do informs and guides criminal investigations and prosecutions when forensic science is involved. In the U.S. and elsewhere, the worlds of academia and the criminal justice system are often one in the same because it’s crime labs that have most of the data and produce many of the scholarly studies. 

America, First 

In October 2015, University of Indianapolis researchers Cynthia Cale, Madison Earll, and two other co-authors became pioneers in American academia. Publishing a study titled, “titled, “Could Secondary DNA Transfer Falsely Place Someone at the Scene of a Crime?,” the paper broke ground by arguing that secondary transfer DNA can lead to false positives in criminal justice investigations and prosecutorial efforts. 

“The experiment designed by Cale and Earll asked pairs of volunteers to shake hands for two minutes, after which they handled knives that were later swabbed for DNA samples,” explained a Science Daily article on the study. “In 85 percent of the cases, DNA from the person who did not directly touch the knife was transferred in sufficient quantity to produce a profile. In one-fifth of the samples, that person was identified as the main or only contributor of DNA to the potential weapon, despite never having touched it.” The startling implications for the criminal justice system cannot be overstated. 

Cale pointed out that the study had come to diametrically different conclusions than other academic literature.

“Most of the articles I’ve read about secondary DNA transfer say there’s not really going to be any impact on the end result,” Cale told Science Daily. “Getting a single-source profile is going to be very hard to dispute in court, but as you can see, that single-source profile could come from a person who hadn’t even touched the knife. The person who handled the knife wasn’t even detected on the knife. And there were other instances where there was a mixture, but the person who didn’t touch it, they were the majority.”

Cale, before going into academia, worked eight years as a forensic scientist with a focus on DNA at a laboratory for the Illinois State Police. She then moved to Indianapolis, where she started the company that she still runs to this day, Strand Analytical Laboratories, and often serves as an expert witness in legal cases. 

Cale also penned a thesis while she was a master’s degree student at the University of Indianapolis on the topic of secondary DNA transfer titled, “Secondary DNA Transfer Revisited: The Impact of the Length of Time of Personal Contact on Secondary DNA Transfer.”

Summarizing her laboratory findings, Cale wrote in the academic journal Nature that forensic DNA evidence should not be regarded as a smoking gun. Rather, it should be analyzed with a critical eye, alongside all other evidence, when someone’s life or liberty is at stake. 

“We urgently need to review how DNA evidence is assessed, viewed and described. Everyone in the medico-legal community — forensic scientists and technicians, DNA analysts, potential jurors, judges and lawyers for both the prosecution and defence— must know and understand the potential for mistakes,” wrote Cale. “It is important to recognize that DNA amplification kits have become much more sensitive than they were in the past. As a result, the types of samples being analyzed have expanded. Investigators no longer need to identify and request analysis of body fluids such as blood, semen and saliva. They can swab surfaces for otherwise invisible cells left behind, on the handle of a weapon or on a windowsill, perhaps, and ask labs to generate a DNA profile from them.”

Importantly, these nuances often go unexplained to jurors in courtrooms nationwide, meaning lay people tend to view DNA as tantamount to foolproof evidence, Cale wrote in Nature. 

Cale’s work and the dynamics unpacked in her Nature article have not gone unnoticed by lawyers, at least in Ohio. In March 2018, the Ohio State Bar Association — the professional collective of attorneys in the Buckeye State — concluded that the criminal justice system should start viewing DNA evidence with a skeptical eye. 

“What should be the concern for everyone involved in our criminal justice system [is] whether misunderstood evidence can cause a miscarriage of justice,” wrote Ohio Bar Association attorney member and criminal defense attorney Joseph Klammer. “Too often technical or scientific evidence is misunderstood by police, prosecutors, defense attorneys and judges. When these actors misunderstand the evidence, there is no reason to believe a jury will not also be misled. The lexicon and technology of this type of DNA must be truly understood and used carefully.”

Greg Hampikian, a biology professor at Boise State University and founder and director of the Idaho Innocence Project, told CLN that he believes that far more could be done on the issue as well. But entities that could do it best fall not only within academia but also within state- and federal-level crime labs—repositories of massive amounts of DNA data that could potentially exonerate those wrongfully convicted of crimes.

“What I like to say is, ‘To grow old is to become embarrassed,’” Hampikian quipped. “You have no choice. If we were to look back 30 years ago, we’d be embarrassed to hear ourselves talk about science, medicine, politics, rights. I don’t blame people for that, but now that we know about these findings, what are we going to do about it?”

Another recent study in the U.S., published by federal researchers from the National Institute of Standards and Technology (“NIST”), also pointed to alarming issues with DNA transfer. But in what Hampikian called “unprecedented,” it includes language in the study calling for its results not to be used within the U.S. court system.

Titled “NIST interlaboratory studies involving DNA mixtures (MIX05 and MIX13): Variation observed and lessons learned,” the paper was published on August 1, 2018, in the journal Forensic Science International: Genetics.

“In the 2005 NIST MIX05 study, 69 laboratories interpreted data in the form of electropherograms of two-person DNA mixtures representing four different mock sexual assault cases with different contributor ratios,” explained the authors of the study’s design. “In the 2013 NIST MIX13 study, 108 laboratories interpreted electropherogram data for five different case scenarios involving two, three, or four contributors, with some of the contributors potentially related.”

Essentially, the study revealed that in the cross-laboratory collaboration with the most laboratories involved — MIX13 — that investigation saw the greatest variation in DNA test results. That variation exhibited many cases of secondary DNA transferred to an item left behind at a mock crime scene, a ski mask. And variation is not something desired when DNA evidence is presented as part of criminal prosecutions due to the “beyond reasonable doubt” standard that exists to protect the accused. 

In an article published by The New York Times in September, Hampikian slammed the way the study’s findings were buried and the carve-out language that could make the paper challenging to cite in criminal cases going forward. 

“I first learned about the results of this study in 2014, at a talk by one of its authors. It was clear that crime labs were making mistakes, and I expected the results to be published quickly,” wrote Hampikian in The New York Times. “Peer-reviewed publication is important, because most judges won’t let you cite someone’s PowerPoint slide in your testimony. But years went by before the study was published, preventing lawyers from using the findings in court, and academics from citing the results in journal articles. If some of us had not complained publicly, it may not ever have been published.”

Despite the paper getting published, Hampikian further wrote in The Times the study’s authors also buried the lede in terms of the magnitude of the findings. And they also inserted language in the study that appears to attempt to block its findings from use in criminal cases. Because the paper was peer-reviewed and published in a journal considered prestigious within forensic science, had that caveat language not been included, it potentially could have been introduced as evidence under the landmark U.S. Supreme Court opinion in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993). The Daubert standard is a federal rule of evidence governing the admissibility of expert witness testimony. It’s the standard for the admissibility of expert witness testimony in federal and most state courts. Importantly, one of the factors that courts are to consider under the Daubert standard is whether the methodology in question has been subjected to peer review and publication. 

Personal Conflicts

“The results described in this article provide only a brief snapshot of DNA mixture interpretation as practiced by participating laboratories in 2005 and 2013. Any overall performance assessment is limited to participating laboratories addressing specific questions with provided data based on their knowledge at the time,” reads the study’s language cited by Hampikian as potential Daubert carve-out language. “Given the adversarial nature of the legal system, and the possibility that some might attempt to misuse this article in legal arguments, we wish to emphasize that variation observed in DNA mixture interpretation cannot support any broad claims about ‘poor performance’ across all laboratories involving all DNA mixtures examined in the past.”

Hampikian told CLN that the co-authors of that study — besides the fact it was published in a federal governmental laboratory — had personal conflicts of interest, which may have moved them to insert such language in the study.

As a case in point, lead author and NIST Special Assistant to the Director for Forensic Science John Butler also serves as the Associate Editor for the journal which published the study. Butler also sits as a member of the FBI’s Scientific Working Group on DNA Analysis Methods and in the past has worked as a Visiting Scientist at the FBI’s lab in Quantico, Virginia. Further, Butler studied under Bruce Budowle, an Associate Editor of Forensic Science International: Genetics journal who worked at the worked as both a research chemist at the Forensic Science Research and Training Center at the FBI Academy and as the chief of the Forensic Science Research Unit in the Laboratory Division at the FBI Academy. Budowle worked for the FBI from 1983-2009, for over 25 years.

Further, Butler studied under Bruce Budowle, an associate editor of the journal Forensic Science International: Genetics and worked as both a research chemist at the Forensic Science Research and Training Center at the FBI Academy and as the chief of the Forensic Science Research Unit in the Laboratory Division at the FBI Academy. Budowle worked for the FBI for over 25 years (1983-2009). 

Butler’s co-author, Michael Coble, also currently works for the federal government apparatus as the director of research at the Armed Forces DNA Identification Laboratory. Alongside Associate Editor Butler, Coble sits on the editorial board for Forensic Science International: Genetics.

Within the field of forensic science, Hampikian told CLN that situations like this are the norm, noting that conflicts of interest can ultimately have a direct impact within the criminal justice system

“That shows you the ridiculous bias that’s built into this so-called scientific community,” Hampikian lamented. “Generally people who come out of police labs, and most of the top people who are on the editorial boards of these forensic science journals, are either from the FBI or similar labs, or trained under those people. And I think there’s a potential for bias and those disclaimers, which are unprecedented in a scientific paper, it shows you what the bent of mind is for people who basically control [the journal].”

Overall, Hampikian says he believes that the field of forensic science has yet to divorce itself from police academies and crime labs, which may go to explain the lack of in-depth focus on the issue of DNA transfer in the U.S. As Exhibit A, he pointed to the fact that NIST’s forensics science unit, headed up by Butler, has been put in charge of doing a federal governmental review of forensic science techniques as a response to recommendations made by the National Academy of Sciences in a 2009 report. 

Across the Pond

Though the U.S. academic community lags behind (and seems uninterested) on the issue of secondary DNA transfer, other countries — particularly European ones — have sailed far ahead in this vital research area. 

One of the first papers to touch on this topic (excuse the pun) came in 1997 by Australian researchers Roland A.H. van Oorschot and Maxwell Jones, also published in the journal Nature. Titled “DNA fingerprints from fingerprints,” the paper is now seen as seminal in applying the precautionary principle to touch DNA and secondary DNA transfer. That paper pointed to the fact that DNA transfer could occur when forensic scientists take DNA swabs. 

“Forensic scientists regularly generate genetic profiles from old blood stains, seminal stains, vaginal swabs, hair, bone, urine and cigarette butts,” the co-authors write in the abstract. “We show that an individual’s genetic profile can now also be generated from swabs taken from objects touched by hands, providing a new tool for crime scene investigations. Our findings also demonstrate the need for caution when handling exhibits and when interpreting results.”

Lead author Van Oorschot, an Australian researcher who works at the Office of the Chief Forensic Scientist for the Victoria Police Forensic Services Department, has persisted with studying the topic for decades and served as lead-author on another paper on the topic of secondary DNA transfer published in Forensic Science International: Genetics. Titled “DNA transfer in forensic science: A review,” the paper serves as a meta-analysis survey of what is known in the field to-date about the phenomenon of secondary DNA transfer by explaining the findings in the most high-profile of papers. Notably, none of the paper’s co-authors hails from the United States; all are based in either The Netherlands, Australia, or Great Britain. 

The paper notes that many examples point to the potential for secondary DNA transfer, but the results are too sporadic and isolated across too many different scenarios to be able to point to big-picture conclusions within academia, let alone within the criminal justice system. 

“This review demonstrates that over the last few years we have become aware of several factors affecting [secondary DNA transfer], but much more research needs to be undertaken to understand the impact of the many variables, build the data necessary to determine probabilities of different profile type occurrences in different situations, and to improve the accuracy of the profile interpretation given the uniqueness of each case scenario to be considered,” they wrote. “As the number of potential scenarios in which [secondary DNA transfer] are to be contemplated is infinite, there will be reliance on extrapolating from research findings. The research thus needs to be of high quality, broad scope, and sufficient quantity.”

Researchers from the Glascow, Scotland-based Forensic Institute have also come to much the same conclusion on the topic. In their 2013 paper “DNA transfer: review and implications for casework,” researchers Georgina Meakin — also a co-author of the recent Van Oorschot paper — and Allan Jamieson did another seminal literature review in the area, concluding that secondary DNA transfer is indeed a thing and must be considered very carefully when dealing with the criminal justice system. 

“It is important to consider indirect transfer in the evaluation of trace DNA in casework. The term ‘trace DNA’ in this review refers solely to DNA that cannot be attributed to an identifiable body fluid,” they wrote in the paper’s abstract. “This review presents and considers data from trace DNA experiments to establish whether the quantity of DNA recovered from a crime stain and/or the quality of a DNA profile obtained can be used to infer the likely mechanism of transfer. The data show that varied results are obtained from apparently similar trace DNA samples, presumably due to the many factors that affect the detection of trace DNA.”

The organization for which they are both affiliated, the the Forensic Institute, has also taken an organizational stand of skepticism on the issue of DNA.

“The detection of a DNA profile upon a surface cannot be considered proof of contact. Research has demonstrated that the quantity of DNA recovered and the quality of DNA profiles obtained are complex issues dependent on many factors,” wrote the Institute. “While direct contact may be the most obvious conclusion, there is insufficient scientific data to establish the most likely mode of transfer in any specific instance. Furthermore, it has also been shown that DNA can be transferred during the forensic examination of items. It may therefore be difficult to rely on the locations of the finding of the DNA to inform on how DNA was deposited.” 

The foregoing notes of caution could potentially have staggering implications for the use of DNA evidence in criminal investigations and prosecutions.    

Many other studies have gone to print on the topic of secondary DNA transfer in recent years as well, penned by scholars from places such as Australia, Italy, Norway, Ireland. Perhaps as a reaction to some of this cornucopia of scholarship, the British House of Lords has assigned its Science and Technology Select Committee to do an in-depth look at various aspects of forensic science within the country’s criminal justice system.

Making Amends

It remains unclear how many people have gone to prison because of DNA samples that were false positives due to secondary transfer. But even one would be too many, said Boise State University’s and the Idaho Innocence Project’s Hampikian.

“Someone could be let out of prison or we could finally catch other rapists or murderers, but the problem is a lot of labs are working on writing new protocols for DNA transfer without protocols for looking back at old cases,” said Hampikian. “It’s not the priority to go back and look at mistakes. Most people do not want to go back and look at their mistakes.”

As a potential solution, Hampikian says a $25,000 reward should be given to any scientist who goes back and finds past mistakes pertaining to DNA transfer issues that could have impacted criminal cases, which results in a reversal of a wrongful conviction. 

“But that’s not how it is,” he said. “Most labs are writing their protocol so that they are not encouraged to look back at old case files.... You’ve got to make amends and you’ve got to fix it.”

As an ethical matter in the field of science, Hampikian said that he sees it as the duty of practitioners not only to make prospective changes in future behavior and conduct but also to look back and heal past wounds from scientific failures. Those failures often have real-world implications for those on the receiving end of the actions taken in the name of science—think wrongful convictions in the criminal justice domain or car accidents for faulty automobiles. 

“It’s not enough to say, ‘Well, we’ve botched all of these other surgeries, and now we know how to do them,’” said Hampikian. “You have a duty to go back and fix them. Just like you can’t say, ‘Well, we know how this plague was spread, but we’ll just let these people die, and now we’re going to go wash our hands.’ No, you’ve got to go back and give those people some medicine.”

Speaking in terms of those hurt by bad science within the criminal justice system, Hampikian raised the rhetorical question: “So, what’s the right medicine for people whose lives were destroyed [by bad DNA science]? What’s the right medicine for them?”

Medicine, of course, cannot be prescribed until the doctor recognizes the issue as a problem requiring medication. In the criminal justice system and forensic science academia in America, alarmingly few even acknowledge that secondary DNA transfer is a problem, so there’s virtually no effort being made to remedy past injustices or safeguard against future ones that will inevitably occur unless the issue of secondary DNA transfer is treated with the urgency it warrants. 



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