Image by Caleb Fisher

Imagine spending 23 years in prison for a crime you didn’t commit, because of dog hair. Santae Tribble was convicted of murder primarily based on the testimony of a forensic scientist. There had been 13 hairs found inside a stocking mask that was about a block away from the murder victim. The hair had been analyzed using microscopic hair analysis, and a forensic scientist claimed that it matched Santae Tribble’s hair. The so-called expert went so far as to testify at trial that there was a 1 in 10 million chance of it being a random chance. The prosecutor relied heavily on this testimony arguing in closing argument that the hair “matched perfectly”.

It was not until over 20 years later, when DNA technology had advanced, that these hairs were put under the scrutiny of DNA testing. Come to find out, he was excluded as being the source of these hairs. And what’s worse, one of the 13 hairs wasn’t even human. It was determined to be canine hair. The “1 in 10 million” testimony about accuracy was so bogus that it couldn’t even be determined the hair was that of the right species. Much less matched to the man who was on trial for his life. And the sad thing is that Santae Tribble’s case is not unique. A 2012 study by the FBI found that in 95% of criminal cases involving hair microscopy evidence, the science used at trial was invalid. (PCAST report p. 3). That is a staggering rate of error. In another study, where hair used in previous trials were DNA tested, 11% of the hair was proved to not match who it was claimed to match. (PCAST report p.3).

These stats are troubling enough on their own. But what makes them so harmful is that studies have shown that jurors falsely believe the error rate of hair microscopy evidence is 1 in 1 million. (PCAST report p. 45). Contrast that with the actual error rate which is closer to 1 in 10 (11%). And you see what a problem we have. The problem is so absurd that John Oliver lampoons it in the attached episode of Last Week Tonight. In the episode, Santae Tribble joked that he thinks the dog was guilty. It’s amazing he’s able to have that sense of humor after suffering such an injustice. You don’t want to put yourself to the test to see if you can laugh about something like this after 20+ years of being wrongly incarcerated. If you’re being falsely accused and hair evidence or other forensic evidence is being used against you, it’s important that your defense strategy involves looking at the underlying error rate of the evidence being used. If the error rate is high, you need to attack that evidence. Nobody should go to prison over evidence that is invalid 95% of the time.