FBI Admits Using Flawed Scientific Evidence In Trials

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Justine Alford

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1682 FBI Admits Using Flawed Scientific Evidence In Trials
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In a harrowing report, the FBI and Department of Justice have admitted that more than 90% of examiners’ testimonies included in an extensive review contained flawed evidence based on a crude hair analysis technique.

The investigation was sparked after three convicted men were cleared of their crimes because the testimony provided by three separate FBI hair examiners was found to be scientifically flawed. The FBI and DOJ subsequently agreed to a comprehensive evaluation of trials that took place between 1980 and 1999, when a simple technique known as microscopic hair analysis was widely used to both eliminate suspects and identify criminals in cases such as rape and murder.


The analysis simply involves examining hairs under a microscope, usually those found at a crime scene and some from a suspect, in order to compare certain characteristics that could indicate that the specimens came from the same individual or someone else. Although the technique still has some use, it has been abandoned by many laboratories in favor of DNA analysis.

As of the year 2000, the FBI began routinely examining the second type of DNA found in cells, called mitochondrial DNA, which can be found in the hair shaft. Our main genome is stored in the nucleus, but as New Scientist points out, analysis can only access this when the root of the hair is still attached. Mitochondrial DNA analysis therefore has its merits and is certainly more reliable than microscopic hair analysis, but it is still imperfect given that mitochondrial DNA is only passed on from the mother, meaning that it would not be able to distinguish between individuals who share the same mother.

After scouring through cases that took place in the two decades preceding the year 2000, the government identified almost 3,000 in which FBI agents may have either submitted reports or testified using microscopic hair analysis. So far, 268 of these have been reviewed, which revealed that 26 out of 28 examiners in the FBI Laboratory’s microscopic hair comparison unit overstated matches that backed prosecution in 96% of the trials, Washington Post reports. And what’s worse, 32 of these cases resulted in death sentences, and 14 of these individuals have either been executed or died in prison.

“These findings confirm that FBI microscopic hair analysts committed widespread, systematic error, grossly exaggerating the significance of their data under oath with the consequence of unfairly bolstering the prosecutions’ case,” Innocence Project co-director Peter Neufeld said in a statement. “While the FBI and DOJ are to be commended for bringing these errors to light and notifying many of the people adversely affected, this epic miscarriage of justice calls for a rigorous review to determine how this started almost four decades ago and why it took so long to come to light.”


Of course, the findings do not necessarily mean that those convicted in trials involving microscopic hair analysis are innocent; however, defendants may now possibly have grounds for appeal and a re-examination of evidence.

[Via Washington Post, the Innocence Project and New Scientist]


  • tag
  • crime,

  • conviction,

  • hair,

  • FBI,

  • DOJ,

  • testimony,

  • microscopic hair analysis