FBI Admits Forensic Experts Gave Flawed Evidence

The FBI has admitted that nearly every forensic expert in its microscopic hair comparison unit gave flawed evidence at trials for more than 20 years before 2000, it has been reported.

Twenty-six of the 28 examiners overstated forensic matches in ways that favoured prosecutors in more than 95% of 268 trials reviewed so far, according to The Washington Post.

The National Association of Criminal Defense Lawyers and the Innocence Project are reviewing questioned forensic evidence and provided the information under a government agreement.

The cases involve 32 defendants who were sentenced to death. Fourteen of those have been executed or died in prison, the newspaper reported.

In a statement to the newspaper, the FBI and US Justice Department said 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."

The FBI has said that hair examiners until 2012 did not have written standards defining scientifically appropriate ways to explain the results in court.

Federal authorities launched an investigation in 2012 after The Washington Post reported that flawed forensic hair matches could have led to the convictions of hundreds of potentially innocent people since the 1970s.

Those convictions were for murder, rape and other violent crimes.

The case reviews confirmed that FBI experts testified to "matches" of crime scene hairs to defendants, using incomplete or misleading statistics to support their arguments.

Since 2000, the laboratory has used visual hair comparison in combination with more accurate DNA testing.