Forensic Pseudoscience
5th February 2019
This past April, the FBI made an admission that was nothing short of catastrophic for the field of forensic science. In an unprecedented display of repentance, the Bureau announced that, for years, the hair analysis testimony it had used to investigate criminal suspects was severely and hopelessly flawed.
The Innocence Project’s M. Chris Fabricant and legal scholar Tucker Carrington classify the kind of hair analysis the FBI performs as “magic,” and it is not hard to see why. By the Bureau’s own account, its hair analysis investigations were unscientific, and the evidence presented at trial unreliable. In more than 95 percent of cases, analysts overstated their conclusions in a way that favored prosecutors. The false testimony occurred in hundreds of trials, including thirty-two death penalty cases. Not only that, but the FBI also acknowledged it had “trained hundreds of state hair examiners in annual two-week training courses,” implying that countless state convictions had also been procured using consistently defective techniques.
I have yet to see any persuasive scientific explanation supporting the common assumption that fingerprints are unique and determinative for identification.