Concerns over safety of thousands of US convictions following criticisms of pioneering DNA analysis

The accuracy of analysis methods used by a pioneering crime laboratory in New York has been called into question, raising concerns about evidence offered in thousands of cases across the USA. Hannah Wilson reports

The respected DNA laboratory of the office of New York City’s chief medical examiner was thought to offer the some of the most sophisticated analysis methods in the country after developing two techniques for analysing particularly challenging DNA samples.

The techniques purported to enable the laboratory to make identifications from samples that were particularly small, or samples which contained a mix of more than one person’s genetic material. As methods used at the New York lab went beyond standard practice at the FBI and other public labs, its reputation spread across the States and it accepted complex samples not only from the New York police, but also from 50 other jurisdictions nationwide.

However, the validity of the analysis methods used is now being held up for scrutiny, with one former member of the New York State Commission on Forensic Science admitting in court testimony that he had been wrong when he approved the use of these methods. Notably, the first expert witness allowed by a judge to examine the software source code behind one technique concluded that its accuracy ‘should be seriously questioned’.

  • You can read Lauren Kirchner’s article in the New York Times, produced in collaboration with ProPublica, HERE.

Earlier in the year, the laboratory stopped the use of the two methods. However, concerns remain about thousands of potentially unsafe convictions in which samples analysed using the disputed methods had been produced.

Defence lawyers are asking the New York State inspector general’s office – the watchdog for the state’s crime laboratories – to launch an inquiry. According to the Legal Aid Society and the Federal Defenders of New York in their letter to the inspector general on Friday, the medical examiner’s office ‘has engaged in negligent conduct that undermines the integrity of its forensic DNA testing and analysis’.

They state that the lab’s actions in keeping the problems with its ‘unreliable’ testing and ‘unsound statistical evidence’ hidden from the public eye and the courts has meant that innocent people may be wrongly convicted, and people guilty of serious crimes may go free.

The inspector general’s office has no jurisdiction over the courts but any finding that the DNA analysis methods used in these cases was flawed could prompt a flurry of litigation; and if it could be shown that the flawed evidence made a clear difference in the outcome of a case, previous convictions could be revisited.

In addition to those who have been convicted using the disputed methods, concerns have also been voiced over the many defendants who chose to plead guilty when they learnt that prosecutors had DNA evidence which would convict them. Should there be a finding that the DNA testing methods were flawed, they would clearly face significant barriers when asking for their case to be reconsidered.

Responding to these developments, the Chief of Laboratories of the medical examiner’s office, Timothy Kupferschmid, has stated that the now obsolete techniques were well-tested and valid, and that the employment of new methods was to keep up with changing FBI standards.


This article was published on September 7, 2017

Profile photo of Hannah Wilson About Hannah Wilson
Hannah is a paralegal at BSB Solictors and is currently completing the BPTC at University of Law in London. She is commissioning editor for the Justice Gap and tweets at @hnnhw3

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