Police Use of DNA: Mistakes, Error and Fraud

DNA Testing is Not Infallible


Do innocent people really have nothing to fear from inclusion in government DNA databases? Bigger databases and expanded collection practices necessarily increase the chance that innocent people will have their DNA taken, used and stored by the state. One issue is whether such people will be falsely accused, and perhaps even convicted, of a crime purely because of false matches and error, which can occur by chance or through poor laboratory/police practice.    Across the world, forensic DNA labs have had problems with cross-contamination of samples, mislabeling, misinterpretation of samples and in some cases outright fraud, including:





  • A review of DNA testing practices in India found that the police have a complete “lack of expertise to collect DNA evidence” as well as there being “a lack of standards, guidelines, accreditation, and proficiency testing of the DNA labs and its experts” which “has resulted in irresponsible and inaccurate application of the technology.”


The consequences can be severe. Consider the case of Adam Scott, who was wrongly accused of raping a woman in Manchester and jailed for 5 months. Phone records later offered an air-tight alibi. A report from the UK forensic science regulator found that the error was the result of “avoidable contamination”.

Or consider the case of Steven Myer, an Ohio man who was indicted for burglary based solely on DNA evidence. He spent seven months in jail before being released after subsequent retesting proved it was not his DNA sample.

Or consider perhaps the case of Lukis Anderson, a California man who was implicated by DNA in the murder of a Silicon Valley millionaire after paramedics who treated him accidentally transferred his DNA to the crime scene when they attended to the victim later the same day.

Indeed, among the first 200 people exonerated with post-conviction DNA testing by the Innocence Project were two men (Timothy Durham and Josiah Sutton) who were convicted in the first place due partly to DNA testing errors.

That the government would obtain DNA from any innocent person is disturbing, but the practice visits a special and severe harm upon minorities. Members of minority groups are arrested in disproportionate numbers, and these individuals are then subject to a higher chance that a false match may implicate them in crimes they did not commit.

The infallibility of DNA tests has, for most purposes, become an accepted fact—one of the shared assumptions underlying the debate over expanded law enforcement uses of DNA. But law enforcement use of DNA requires human intervention at every instance; from the taking of samples, to their transportation, testing, evaluation and reporting. Such interventions allow for error at every stage of the testing process.

If your profile is in a DNA database you face higher risk than other citizens of being falsely linked to a crime. You are at higher risk of false incriminations by coincidental DNA matches, by laboratory error, and by intentional planting of DNA. There can be no doubt that database inclusion increases these risks.

© 2014 Forensic Genetics Policy Initiative