Part two of Pamela Colloff’s ProPublica/New York Times “Blood Will Tell” investigation into the faulty forensic “science” of blood spatter analysis came out today. It’s a sobering look at the reliability — or lack there of — of what has become an important crime scene investigation technique, and anyone who cares about criminal justice or understands forensics only via Dexter should read it. If you haven’t yet read part one, which details the unlikely arrest and conviction of Joe Bryan for the murder of his wife, Mickey, now’s the time:

When Robert Thorman settled into the witness box on the fifth and final day of the state’s case, it marked a turn in the prosecution’s fortunes. Thorman was the bloodstain-pattern analyst who was called to the Bryan home when investigators were still working the scene. As an interpreter of bloodstains, Thorman possessed a singular expertise, and the prosecution would use this to bring its hazy narrative into focus, lending a sense of scientific certainty to an otherwise equivocal set of facts…

The district attorney began by leading Thorman through a recitation of his credentials. The detective explained that he had served as a military police officer for 20 years before working his way up through the ranks of several small law-enforcement agencies and that he had been trained in bloodstain interpretation. The jury did not know that Thorman’s training was limited to a 40-hour class he took four months before Mickey was killed.

Bryan was convicted despite a complete lack of other forensic evidence (in fact, there was evidence that pointed away from him), an extremely improbable timeline, and no motive; there is zero evidence that he was anything other a supportive husband who was deeply in love with his wife. Then he got a re-trial, and was convicted a second time on the same shoddy evidence.

Thorman told the jury not only that the flashlight was in the bedroom at the time of the shooting but also that the killer, before fleeing the scene, had changed into clothes that were already in the Bryan home. He delivered his findings with the authority of an expert, stripping away the ambiguities of the state’s case. As he spoke to the jury, he grounded his findings in the certainty of science. “Based on my knowledge and experience in bloodstain interpretation,” he said, “the flashlight itself was right next to or near the source of energy, that being the gun.” By the time the guilty verdict came down on the last day of the trial, it seemed like a foregone conclusion. Joe was again sentenced to 99 years.

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