That's the title of Dave Mann's latest article on faulty forensics in the Texas Observer. It's subtitled, "Warren Horinek was a vicious drunk with a history of threatening his wife. But his conviction for murdering her was based on junk science--like thousands of others." Two brief excerpts from this must-read:
From the start, Warren Horinek has claimed his wife shot herself. As the police investigation unfolded, the people normally responsible for sending a murderer to prison—the crime scene investigator, the police sergeant who oversaw the homicide investigation, the medical examiner who performed the autopsy, even the assistant district attorney initially assigned to prosecute the case—all came to believe that Horinek was telling the truth.
When Horinek was tried for murder, they testified in his defense. Their testimony and expertise wouldn’t matter. Horinek’s fate would hinge on a few specks of blood found at the scene. A few specks of blood, that is, along with the testimony of a single forensic expert who may have misread the evidence. As a result, an innocent man may spend decades in prison. He won’t be alone.
And:
For most of his trial, Horinek’s attorney seemed prescient. The jury appeared to be convinced of his innocence. Later, when this anything-but-textbook trial was over, the foreman would say that the jurors were going to acquit Horinek. That was before the prosecution’s final witness took the stand. This case, like hundreds of others, was decided by the testimony of a single forensic expert.
His name is Tom Bevel. He’s a private, Oklahoma-based expert in bloodstain patterns. The study of blood spatter has been around since the 1890s. But unlike other forensic evidence—DNA or fingerprinting, for example—blood spatter evidence rarely provides the sole basis for prosecution. Blood patterns—like those found on Warren Horinek’s Hard Rock Cafe T-shirt that night in 1995—can be used to augment evidence in a criminal case, but they’re rarely the only evidence. The reason is simple: Bloodstains can tell you only so much about who committed a crime, or how. Some experts, Bevel included, have tried to use blood-spatter forensics to reconstruct where blood came from and by what method. If that sounds fantastical, it sometimes is.
In recent years, flawed blood-spatter evidence has led to at least three wrongful convictions across the country, from North Carolina to Indiana. In 2009, the National Academy of Sciences released findings from the most extensive study ever conducted of forensic evidence in American courtrooms. The authors didn’t think much of blood-spatter analysis, writing that the “uncertainties associated with bloodstain pattern analysis are enormous,” and concluding that the opinions of blood-spatter experts like Bevel are “more subjective than scientific.”
In that respect, bloodstain analysis is similar to other kinds of forensic science. With the exception of DNA testing, much of the forensic evidence used in U.S. courts—including fingerprint matches, ballistics, and arson evidence—is based on junk science. CSI it ain’t. Contrary to what’s portrayed on television, bullets are regularly matched to the wrong gun, fingerprints are misidentified, crime labs botch their analysis, and accidental fires are misread as arson.
Most criminal-justice experts believe that flawed forensic evidence—and overreaching expert witnesses—have sent thousands of Americans to prison for crimes they didn’t commit. The solution is to ensure that forensic testimony is based on sound science.
Mann's earlier investigative journalism is noted here.
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