2015/04/24

Ars Technica April 23, 2015: The Science (and lack thereof) Behind the FBI's Retreat on Hair Analysis

It was a long road to an admission that agents systematically overstated evidence.

Donald Eugene Gates served 27 years in prison for armed murder and rape, seven years past the length of his minimum sentence. He was sent to prison in part due to the testimony of informants and in part due to forensic analysis of hair associated with the case. In 2009, however, DNA evidence indicated that he was not guilty of the crime.

On Monday, the FBI released what was almost certainly a painful admission: this case was not unusual. The vast majority of the agents that it had sent to court to testify about a specific forensic analysis had submitted erroneous statements to the court. In its preliminary review of relevant cases, at least 90 percent of them were problematic.

The technique in question is hair analysis, in which forensic specialists attempt to match features of hairs associated with a crime to either a suspect or a victim. Prior to the advent of widespread DNA testing in the '90s, this technique was used in thousands of cases as evidence tying a suspect to a specific crime; the Bureau discontinued its reliance on it in 1996. But the issue was revived in 2009, when the National Academies of Science performed a systematic review of the forensic sciences. That review set in motion a process that is just now bearing fruit. more