The FBI has admitted that most of the experts in its forensic unit gave flawed testimony over two decades. This testimony was crucial in several rape and murder cases, some of which carried the death penalty.
The US domestic intelligence service admitted officially that the Washington Post revelations on Saturday were correct. The paper had reported that 26 of 28 examiners with the FBI's microscopic hair comparison unit had overstated matches of hair at crime scenes in ways that favored the prosecution's cause. Wrong evidence was included in over 95 percent of the 268 trials reviewed for the twenty year period leading up to 2000.
The paper quoted the National Association of Criminal Defense Lawyers and the Innocence Project's post-conviction review and found that of the 32 defendants who were sentenced to death during that time, 14 had been executed or had died in prison.
Peter Neufeld, co-founder of the Innocence Project, commended the FBI and department for their collaboration but said, “The FBI's three-decade use of microscopic hair analysis to incriminate defendants was a complete disaster.”
The review of a total of 2,000 criminal cases in which the FBI conducted microscopic hair analysis of crime scene evidence is being conducted under an agreement with the US government. It was launched after three men were exonerated by DNA evidence in three separate cases where different FBI analysts had provided scientifically invalid evidence
Before DNA testing was used in criminal trials, prosecutors routinely relied on microscopic hair comparison analysis, to link a criminal defendant to a crime. But there are significant limitations on the value of such analysis because when examining samples under a microscope, it can't be ruled out that the hairs of two different people seemed like hairs from the same person. Only the combination with DNA testing can bring certainty
“It appears that in many cases the FBI analysts were overstating the significance of these similarities, often leaving juries with the false impression that a hair recovered from the crime scene must have come from the defendant and could not have come from anyone else,” said Neufeld.
The report reveals one of the US's biggest legal scandals, revealing that the courts had failed to recognize dubious scientific information that contributed to wrongful convictions in more than a quarter of 329 cases since 1989 where defendants were later exonerated on the basis of DNA evidence.
In a statement, the FBI and Justice Department vowed to continue to devote resources to address all cases and said they “are also committed to ensuring the accuracy of future hair analysis testimony, as well as the application of all disciplines of forensic science.”