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STRmix precluded as inadmissible DNA evidence in Hillary case
A St. Lawrence County judge ruled that STRmix cannot be used as DNA evidence in the trial of New York v. Oral Nicholas Hillary. Hillary, 42, is accused of murdering Garrett Phillips, 12, of Potsdam, NY. The trial is scheduled to start next month.
Hillary’s lawyers had filed a motion "to preclude the prosecution from offering expert testimony as to the use of, or any results produced by, the forensic software tool STRmix." The defense alleged that "the use of this software for probabilistic genotyping is not generally accepted in the relevant scientific community and legal communities as required by Frye v. United States."
The judge granted the defense motion "to preclude the prosecution from calling an expert witness to testify on their direct case regarding any conclusion reached by the use of STRmix."
Cybergenetics TrueAllele® technology examined over a hundred items, and showed that Hillary was not connected to the DNA evidence in this case. Prosecutors later retained DNA expert Dr. John Buckleton, an employee of New Zealand’s ESR company.
Dr. Buckleton used his STRmix software, and a second method called random match probability (RMP), to analyze DNA data from the victim’s fingernails. He found an association. Dr. Buckleton told the court his "recommendation is to validate" STRmix in-house, which was not done. He also said "RMP overstates the weight of evidence in this case."
The defense submitted a response letter to Judge Catena on August 24. In Exhibit B, Dr. Mark Perlin of Cybergenetics described how picking data gave a biased result. "Buckleton chose a threshold of 50 rfu. But the fingernail evidence contains potentially exculpatory evidence between 30 and 50 rfu. And STRmix is validated for using more peaks at 30 rfu, not fewer at the higher 50 rfu level."
The Exhibit continued, "In fact, running STRmix at a validated 30 rfu threshold would exclude Hillary. The fingernail evidence is exculpatory. STRmix proves that Hillary’s DNA is not present."
"Eliminating human bias is essential in forensic science," said Dr. Perlin. "Failed mixture interpretation methods of the past should not be perpetuated into the future." TrueAllele is accurate and unbiased – all DNA data goes in, without human interference.
- DNA analysis admissibility - Decision & Order
- Tensions simmer as a small town seeks answers in a boy’s killing - NY Times
- Judge rejects DNA test in trial over Garrett Phillips’s murder - NY Times
- Misinterpretation of DNA evidence - Exhibit B
- Overcoming bias in DNA mixture interpretation - Cybergenetics
- Failing to interpret DNA mixture evidence - Cybergenetics