The Pittsburgh Post-Gazette/ Ipso Facto
August 2, 2013
The Cautionary Instruction has periodically examined the fallibility of long accepted forms of scientific evidence used in criminal cases. This blog has explored fingerprint analysis, bite mark identification and even eyewitness identification. Last month, the FBI announced that the agency will review thousands of old cases in which microscopic hair analysis helped secure convictions.
More than 2,000 cases processed from 1985 to 2000 will be re-examined, including some in which execution dates had been set.
The study will focus on whether analysts exaggerated the significance of their hair analyses or reported them inaccurately. Defendants will be notified and free DNA testing offered if errors are unearthed.
Three hundred and ten individuals have been exonerated through DNA evidence, according to an Innocence Project database, 72 were convicted in part because of microscopic hair evidence.
In addition, as many as 27 prisoners facing the death penalty may have been wrongfully convicted based on microscopic hair analysis.
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.
Since at least the 1970s, written FBI Laboratory reports typically stated that a hair association could not be used as positive identification. For years some agents 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.
FBI Special Agent Ann Todd says "there is no reason to believe the FBI Laboratory employed 'flawed' forensic techniques," adding that microscopic hair analysis is "a valid forensic technique and one that is still conducted at the lab" alongside DNA testing. Todd notes "the purpose of the review is to determine if FBI Laboratory examiner testimony and reports properly reflect the bounds of the underlying science."
“When there’s a problem, you have to face it, and you have to figure out how to fix it, move forward and make sure it doesn’t happen again,” said FBI general counsel Andrew Weissmann.
Although the FBI continues to supports hair analysis, the accuracy of hair analysis is not clear. A 2009 National Academy of Sciences report found no good studies of the technique's error rates. The academy concluded that hair analysis has "limited probative value" and isn't able to pinpoint individual defendants.
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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.
Since at least the 1970s, written FBI Laboratory reports typically stated that a hair association could not be used as positive identification. For years some agents 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.
FBI Special Agent Ann Todd says "there is no reason to believe the FBI Laboratory employed 'flawed' forensic techniques," adding that microscopic hair analysis is "a valid forensic technique and one that is still conducted at the lab" alongside DNA testing. Todd notes "the purpose of the review is to determine if FBI Laboratory examiner testimony and reports properly reflect the bounds of the underlying science."
“When there’s a problem, you have to face it, and you have to figure out how to fix it, move forward and make sure it doesn’t happen again,” said FBI general counsel Andrew Weissmann.
Although the FBI continues to supports hair analysis, the accuracy of hair analysis is not clear. A 2009 National Academy of Sciences report found no good studies of the technique's error rates. The academy concluded that hair analysis has "limited probative value" and isn't able to pinpoint individual defendants.
Visit Ipso Facto
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