WASHINGTON - The US Justice Department and FBI have formally acknowledged that nearly every examiner in an elite FBI forensic unit gave flawed testimony in almost all trials in which they offered evidence against defendants over more than a two-decade period before 2000.
Of 28 examiners, 26 overstated forensic matches in ways that favoured prosecutors in more than 95 per cent of the 268 trials reviewed so far, according to National Association of Criminal Defense Lawyers and the Innocence Project, which are assisting the government with the largest post-conviction review of questioned forensic evidence.
The cases include those of 32 defendants sentenced to death 14 of which have been executed or died in prison.
The admissions mark a watershed in one of the largest forensic scandals, highlighting the failure of the courts to keep bogus scientific information from juries, legal analysts said.
Now the question is how authorities and the courts will respond to findings that confirm long-suspected problems with subjective, pattern-based forensic techniques - like hair and bite-mark comparisons - which have contributed to wrongful convictions in more than one-quarter of 329 DNA-exoneration cases since 1989. National Registry of Exonerations
Peter Neufeld, 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."
The FBI and Justice Department vowed to continue to devote resources to address all cases and said they "are committed to ensuring that affected defendants are notified of past errors and that justice is done in every instance and also to ensuring the accuracy of future hair analysis, as well as the application of all disciplines of forensic science".
The FBI is waiting to complete all reviews to assess causes but has acknowledged that hair examiners until 2012 lacked written standards defining scientifically appropriate and erroneous ways to explain results in court. The bureau expects to complete similar standards for testimony and lab reports for 19 forensic disciplines.
It will include cases conducted by all hair and fiber examiners since at least least 1985 and may reach earlier if records are available.
Federal authorities launched the investigation in 2012 after The Washington Post reported Justice Department officials had known for years that flawed forensic work might have led to the convictions of potentially innocent people since at least the 1970s, typically for murder, rape and other violent crimes but had not performed a thorough review of the cases.
In addition, prosecutors did not notify defendants or their attorneys even in many cases they knew were troubled.
The review confirmed that FBI experts systematically testified to the near-certainty of "matches" of crime-scene hairs to defendants, backing their claims by citing incomplete or misleading statistics drawn from their case work.
See the PBS NOVA feature: Forensics on trial
Officials started reviewing the cases in the 1990s after reports that sloppy work by examiners at the FBI lab was producing unreliable forensic evidence in trials.
In addition, they reviewed only a limited number of cases and focused on the work of one scientist despite warnings that problems were far more widespread and could affect potentially thousands of cases.
In the discipline of hair and fiber analysis, only the work of FBI Special Agent Michael Malone was questioned. Even though they knew the discipline had weaknesses and the lab lacked protocols - and learned that examiners' "matches" were often wrong - they kept their reviews limited to Malone.
In one Texas case, Benjamin Herbert Boyle was executed in 1997, more than a year after the review began. Boyle would not have been eligible for the death penalty without the FBI's flawed work, according to a prosecutor's memo.
The case of a John Norman Huffington serving a life sentence for a 1981 double killing is another in which law enforcement officials knew of forensic problems but never told the defendant. Attorneys for Huffington say they learned of potentially exculpatory Justice Department findings from The Washington Post. They are seeking a new trial.
Donald E. Gates, 60, served 28 years for the rape and murder of a university student based on Malone's testimony that his hair was found on the victim's body. He was exonerated by DNA testing in 2009. But for 12 years before that, prosecutors never told him about the inspector general's report about Malone, that Malone's work was key to his conviction or that Malone's findings were flawed, leaving him in prison the entire time.
John McCormick, 63, had just finished the night shift driving a taxi on July 1978. He reached the doorstep of his home about 3 AM, when he was robbed and fatally shot by a man in a stocking mask, according to his widow, who caught a glimpse of the attack from inside the house.
Police soon focused on Santae Tribble. A police informant said Tribble told her he was with his childhood friend, Cleveland Wright, when Wright shot McCormick.
After a three-day trial, jurors deliberated two hours before asking about a stocking found a block away which had been recovered by a police dog. It contained a single hair the FBI traced to Tribble. Forty minutes later, the jury found him guilty of murder. He was sentenced in January 1980 to 20 years to life in prison.
Tribble, 17 at the time, his brother, his girlfriend and a houseguest all testified that they were together preparing to celebrate the guest's birthday the night McCormick was killed. All four said Tribble and his girlfriend were asleep between 2 and 4:30 AM. Santae Tribble took the stand in his own defense, saying what he had said all along - that he had nothing to do with McCormick's killing.
The prosecutor, David Stanley, began his closing argument by citing the FBI's testimony about the hair from the stocking and went further as he summed up the evidence. "There is one chance, perhaps for all we know, in 10 million that it could [be] someone else's hair," sounding the final word for the government.
After a year-long effort to have DNA evidence retested, Tribble's public defender succeeded and turned over the results from a private lab to prosecutors. None of the 13 hairs recovered from the stocking - including the one that the FBI said matched Tribble's - shared Tribble's or Wright's genetic profile, conclusively ruling them out as sources, according to mitochondrial DNA analyst Terry Melton of the private lab.
"The entire theory of prosecution - that Tribble and Wright acted together to kill McCormick - is demolished," wrote Sandra Levick, chief of special litigation for the D.C. Public Defender Service and the lawyer who represents Tribble.
Santae Tribble served 23 years in prison, with an additional 5 for parole violations.
The FBI scientist who originally testified at Tribble's trial, Special Agent James Hilverda, said all the hairs he retrieved from the stocking were human head hairs, including the one suitable for comparison that he declared in court matched Tribble's "in all microscopic characteristics."
Harold Deadman, a senior hair analyst with the D.C. police who spent 15 years with the FBI lab, forwarded the evidence to the private lab and reported the 13 hairs he found included head and limb hairs. One exhibited Caucasian characteristics, Deadman added. Tribble is black.
But the private lab's DNA tests irrefutably showed the 13 hairs came from three human sources, each of African origin, except for one - which came from a dog.
"Such is the true state of hair microscopy," Levick wrote. "Two FBI-trained analysts, James Hilverda and Harold Deadman, could not even distinguish human hairs from dog hairs."
Popularized in fiction by Sherlock Holmes, hair comparison became an established forensic science by the 1950s. Before modern-day DNA testing, hair analysis could, at its best, accurately narrow the pool of suspects to a class or group or definitively rule out a person as a possible source.
But in practice, even before the "CSI effect" led jurors to expect scientific evidence at every trial, a claim of a hair match packed a powerful, dramatic punch in court. The testimony, usually by a respected scientist, allowed prosecutors to boil down ambiguous cases for jurors to a single, incriminating piece of human evidence left at the scene.