Hundreds of convictions in doubt as FBI admits hair-match 'exaggeration'

Juries were always told that hair-analysis testimony from government experts was unimpeachable. Photo / File

Hundreds and potentially thousands of past convictions for serious crimes including rape and murder have been thrown into doubt in the US by a startling acknowledgement by the FBI that for two decades its forensic experts consistently overstated the significance of hair matches to favour prosecutors.

Revealing the scope of the scandal, the FBI has said that 26 of the 28 examiners in its laboratory handling microscopic hair analysis exaggerated their findings in 95 per cent of the 268 trials reviewed so far in the two decades from 2000. And the probe is far from over. Altogether, 2500 cases where hair-matches between victims and defendants were a factor in convictions have been targeted for review.

Juries were always told that hair-analysis testimony from government experts was unimpeachable. But the FBI says that written standards defining how hair-based evidence should be used in court were only provided to analysts in 2012. Meanwhile it appears the analysts repeatedly testified to "near-certain" matches of hair found on victims with that of defendants, relying on faulty statistics from previous cases.

According to The Washington Post, which reported the findings yesterday, the FBI and the Justice Department have been pursuing the investigation with help from two non-governmental bodies, the National Association of Criminal defence Law and the Innocence Project. The two organisations had agreed with the government not to share any of the findings until at least 200 cases had been reviewed.

It was a report by the Post in 2012 suggesting innocent defendants may have been sent to prison, and in some cases death row, based on bogus testimony that first spurred the probe. Among those cases so far reviewed, 32 involved defendants who were sentenced to death, of whom 14 have been executed or died in prison.

The Post last night pointed out that convictions in some of the cases may yet have been well-founded because of other evidence presented by prosecutors. But meanwhile, prosecution services and defendants in 46 states and Washington DC have been notified that the problem could form a basis for appeals. The extent of the disaster is highlighted by Washington DC. The only judicial district to have re-examined all of the hair-evidence cases identified for review, it found that three of seven defendants convicted after dodgy FBI testimony have been exonerated since 2009 after further DNA analysis, while the courts separately exonerated two others. All five spent 20 to 30 years in prison for rape or murder.

In a joint statement the FBI and the Justice Department pledged to continue the review, insisting they "are committed to ensuring that affected defendants are notified of past errors and that justice is done in every instance". They added: "The Department and the FBI are also committed to ensuring the accuracy of future hair analysis, as well as the application of all disciplines of forensic science."

Peter Neufeld, co-founder of the Innocence Project, said: "The FBI's three-decade use of microscopic hair analysis to incriminate defendants was a complete disaster. We need an exhaustive investigation that looks at how the FBI, state governments that relied on examiners trained by the FBI and the courts allowed this to happen and why it wasn't stopped much sooner."

New developments in DNA testing makes hair-matching more reliable today. But until the late-1990s there was in fact little reliable science on the extent to which hair samples from different human beings differed from one another.

- The Independent