Forensic Scientists Often Produce Dubious Results

For decades, flawed and fabricated evidence has been used to convict innocent people
By Mike L. Ford,  Newser Staff
Posted May 28, 2022 4:00 PM CDT
Crime Labs Often Reach Dubious Conclusions
Stock photo.   (Getty/digicomphoto)

G. Michele Yezzo worked for 32 years as a forensic scientist in Ohio. She resigned in 2009, after being reprimanded by her supervisor for "interpretational and observational errors" that "could lead to a substantial miscarriage of justice." By then, Yezzo had amassed a 449-page personnel file loaded with serious behavior complaints and disparaging reports about her work in a slew of major cases. Yezzo is the central figure in an Atlantic article by Barbara Bradley Hagerty, which questions whether forensic science can be trusted. It's not a new question; indeed, a "bombshell" 2009 report by the National Academy of Sciences found a system riddled with errors and flawed methods.

The system hasn't changed in any meaningful ways: Most crime labs are still not independent but embedded in police departments, and the work they do is not subject to any rigorous regulations or standards. Some fields like toxicology and DNA analysis rest on firm scientific ground, but many are prone to cognitive bias—the tendency of analysts (and/or detectives and prosecutors) to see what they want to see. Bite marks, bloodstains, and hair analysis are especially faulty, but prosecutors know juries are suckers for "expert" testimony. Furthermore, as numerous convictions overturned by the Innocence Project and others have revealed, flawed and fabricated evidence is often central to cases in which police and prosecutors suppress exculpatory evidence. Yezzo is retired now, but she faces lawsuits, and her career left many innocent lives in tatters. Read more here. (More crime lab stories.)

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