An unprecedented federal review of old criminal cases has uncovered as many as 27 death penalty convictions in which FBI forensic experts may have mistakenly linked defendants to crimes with exaggerated scientific testimony, U.S. officials said.
The review led to an 11th-hour stay of execution in Mississippi in May.
It is not known how many of the cases involve errors, how many led to wrongful convictions or how many mistakes may now jeopardize valid convictions. Those questions will be explored as the review continues.
The discovery of the more than two dozen capital cases promises that the examination could become a factor in the debate over the death penalty. Some opponents have long held that the execution of a person confirmed to be innocent would crystallize doubts about capital punishment. But if DNA or other testing confirms all convictions, it would strengthen proponents’ arguments that the system works.
FBI officials discussed the review’s scope as they prepare to disclose its first results later this summer. The death row cases are among the first 120 convictions identified as potentially problematic among more than 21,700 FBI Laboratory files being examined. The review was announced last July by the FBI and the Justice Department, in consultation with the Innocence Project and the National Association of Criminal Defense Lawyers (NACDL).
The unusual collaboration came after The Washington Post reported last year that authorities had known for years that flawed forensic work by FBI hair examiners may have led to convictions of potentially innocent people, but officials had not aggressively investigated problems or notified defendants.
At issue is a once-widespread practice by which some FBI experts exaggerated the significance of “matches” drawn from microscopic analysis of hair found at crime scenes.
Since at least the 1970s, written FBI Laboratory reports typically stated that a hair association could not be used as positive identification. However, on the witness stand, several agents for years went beyond the science and testified that their hair analysis was a near-certain match.
The new review listed examples of scientifically invalid testimony, including claiming to associate a hair with a single person “to the exclusion of all others,” or to state or suggest a probability for such a match from past casework.
Whatever the findings of the review, the initiative is pushing state and local labs to take similar measures.
For instance, the Texas Forensic Science Commission on Friday directed all labs under its jurisdiction to take the first step to scrutinize hair cases, in a state that has executed more defendants than any other since 1982.
Separately, FBI officials said their intention is to review and disclose problems in capital cases even after a defendant has been executed.
“We didn’t do this to be a model for anyone — other than when there’s a problem, you have to face it, and you have to figure how to fix it, move forward and make sure it doesn’t happen again,” FBI general counsel Andrew Weissmann said. “That tone and approach is set from the very top of this building,” he said, referring to FBI Director Robert S. Mueller III.
David Christian “Chris” Hassell, director of the FBI Laboratory, said the review will be used to improve lab training, testimony, audit systems and research, as it has done when previous breakdowns were uncovered. The lab overhauled scientific practices when whistleblowers revealed problems in 1996 and again after an FBI fingerprint misidentification in a high-profile 2003 terrorism case, he said.
“One of the things good scientists do is question their assumptions. No matter what the field, what the discipline, those questions should be up for debate,” Hassell said. “That’s as true in forensics as anything else.”
Advocates for defendants and the wrongly convicted called the undertaking a watershed moment in police and prosecutorial agencies’ willingness to re-open old cases because of scientific errors uncovered by DNA testing.
Peter J. Neufeld, co-founder of the Innocence Project, which supports inmates who seek exoneration through DNA testing, applauded the FBI, calling the review historic and a “major step forward to improve the criminal justice system and the rigor of forensic science in the United States.”
Norman L. Reimer, executive director of the NACDL, also praised the effort, predicting that it would have “an enormous impact on the states” and calling on the defense bar to represent indigent convicts.
“That’s going to be a very big job as this unfolds,” said Reimer, whose group has spent 1,500 hours identifying cases for the second round of review.