Defense tries new tack to fight DNA evidence in double homicide case
Attorneys arguing TrueAllele DNA analysis software is 'novel' science
November 22, 2016 12:21 AM
Defense attorneys Ken Haber, left, and Noah Geary filed a new motion alleging that TrueAllele is “novel” and does not have “general acceptance in the scientific community.”
By Paula Reed Ward / Pittsburgh Post-Gazette
Defense attorneys for Michael Robinson have tried everything to challenge DNA evidence against their client for a 2013 double homicide in Duquesne.
First they asked Allegheny County Common Pleas Court to order Cybergentics’ founder Mark Perlin to turn over the source code for his computer program, TrueAllele, which links Mr. Robinson to a black bandanna found near the crime scene.
They argued that Mr. Robinson has a right to confront his accuser at trial, and without knowing what the computer program does, they can’t properly challenge the evidence.
But they were rejected by Judge Jill E. Rangos and took the issue to the state Superior Court. When that failed, they asked the state Supreme Court for relief.
They were rejected there, too, and have now filed a new motion alleging that TrueAllele is “novel” and does not have “general acceptance in the scientific community.”
Judge Rangos will listen to the argument today to decide whether Mr. Robinson is entitled to have a hearing on that issue.
Defense attorneys Ken Haber and Noah Geary based their most recent motion on a September report from the President’s Council of Advisors on Science and Technology, a commission of scientists and engineers appointed by President Barack Obama to explore the validity of forensic evidence in the aftermath of a 2009 report that was highly critical of a number of fields of forensic science.
The new report, “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods,” examines a number of forensic sciences, including bitemark, fingerprint, hair and firearms analysis.
It also evaluated DNA analysis in samples involving a single-source and mixtures.
The report spends about seven of its 160 pages addressing complex DNA mixtures — like those that exist in the Robinson case — and notes that probabilistic genotyping software programs like TrueAllele “clearly represent a major improvement over purely subjective interpretation.” But it continues, “they still require careful scrutiny to determine (1) whether the methods are scientifically valid, including defining the limitations on their reliability (that is, the circumstances in which they may yield unreliable results) and (2) whether the software correctly implements the methods. This is particularly important because the programs employ different mathematical algorithms and can yield different results for the same mixture profile.”
The report recommends that the programs be studied by multiple groups not associated with the software developers.
In its conclusion, the commission wrote that two most widely used programs, STRMix and TrueAllele, “appear to be reliable within a certain range, based on the available evidence and the inherent difficulty of the problem,” and that they have “foundational validity” in mixtures of three people, provided the minor contributor makes up at least 20 percent of the DNA in the sample.”
In Mr. Robinson’s case, his attorneys said, Dr. Perlin previously testified that the bandanna could be a three-person mixture, with the minor contributor making up only 10 percent of the DNA.
“Perlin’s methodology fails to meet PCAST’s threshold for reliability and general acceptance in the relevant scientific field,” they wrote. “His findings are therefore inadmissible at trial.”
But in his response, Daniel E. Fitzsimmons, the chief trial deputy district attorney, said the PCAST report is inadmissible hearsay and would not be permitted at trial. More than that, though, he believes that the defense misunderstood Dr. Perlin’s testimony. In Mr. Robinson’s case, the prosecutor said, the defendant would have contributed approximately 45 percent of the DNA in the mixture.
The defense attorneys are misinterpreting the PCAST report if they believe that none of the DNA in a three-person mixture should be considered if the minor contributor is less than 20 percent — even if the suspect contributed the majority of DNA, Mr. Fitzsimmons wrote.
“Clearly defendant’s strained interpretation cannot be the intended result since it would produce absurd outcomes where mixtures with only trace contributors to an otherwise almost entirely one-person sample would need to be excluded,” the prosecutor said in his brief. ”More importantly, though, is the fact that the authors of the PCAST report cite absolutely no authority or support for their statement on which defendant now relies about the supposed ‘20 percent contribution minimum’ for minor contributors.”
Mr. Fitzsimmons continued, “While this unsupported statement might be perfectly acceptable in a policy recommendation paper to the president, it does not provide reliable support for defendant’s underlying contention that the PCAST report has directly undermined the Superior Court’s precedential holding in Foley based upon a legitimate dispute among scientists in the relevant field.”
He was referring to the 2012 case of the Commonwealth v. Kevin J. Foley, a Pennsylvania state trooper convicted of killing a Blairsville dentist. In that Superior Court decision out of Indiana County, the appellate court found that Dr. Perlin’s testimony regarding TrueAllele was not novel and therefore was permitted at trial.
In the Robinson case, the commonwealth argued, the defense failed to plead facts sufficient to prove at a hearing that “the scientific evidence at issue is ‘novel,’ ” or that “there is a legitimate dispute among scientists in the relevant field about scientific methodology at issue.”
Mr. Robinson’s trial is scheduled to begin on Jan. 9.
Paula Reed Ward: firstname.lastname@example.org, 412-263-2620 or on Twitter: @PaulaReedWard.
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