Sorry, Dexter: Blood Spatter Analysis May Be Bogus

ProPublica looks at how one man nearly single-handedly created the field
By John Johnson,  Newser Staff
Posted Dec 14, 2018 8:25 AM CST
Blood Spatter Analysis May Be 'Junk Science'
A plastic-wrapped 'kill room' is prepared by set dresser Rodney Rosene on the set of the Showtime original series "Dexter" in Los Angeles.   (AP Photo/Chris Pizzello)

It looks like unassailable science when presented on shows like Dexter or CSI, and, far more significantly, in countless courtrooms across the nation. But as a report in ProPublica explains, the science behind blood-spatter analysis may not be as sound as people think. The story looks at how one man, a scientist named Herb MacDonell who worked at Corning Glass Works in New York, all but single-handedly created the field as it exists today. MacDonell began dabbling in his off-hours as a forensics consultant and testified in his first trial in 1968. He turned his home basement into the Laboratory of Forensic Science and named himself director. "In time, MacDonell would testify and publish books and articles using this official-sounding moniker," writes Leora Smith. "Few realized the limited scale of the operation."

MacDonell argued that he and those he trained—graduates formed the International Association of Bloodstain Pattern Analysts—could tell much about a crime scene from the way blood spattered. Even though some attorneys and judges doubted the science along the way, this kind of testimony "spread through courtrooms across the country like a superbug," writes Smith. MacDonell himself even testified in the OJ Simpson trial. In 2009, the National Academy of Sciences found that “the uncertainties associated with bloodstain pattern analysis are enormous," concluding that analysts' findings were generally "more subjective than scientific." The report did little to slow the tide, though Smith talks to one former judge who is trying to instruct attorneys how to challenge the "junk science." Click for the full story, which includes an interview with the unrepentant MacDonell, now 90. (Read more forensic experts stories.)

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