One of the reasons innocent people are found guilty is because overzealous police and prosecutors commit misconduct, mainly because they think the defendant is guilty and they can’t take a chance on seeing a “guilty person” go free. You would think that scientists in a lab would have no axe to grind and would just call them as they see them.
While it’s true that most forensic crime lab analysts do exactly that, not all of them do. Some, for whatever reason (and there have been a variety of them), try to “help” the prosecutors by shading their testimony towards that which will convict and away from the truth.
One of the most common way this happens is when a forensic analyst overstates his or her findings to mean more (or less) than they really do. In this new article from ProPublica, a Texas Forensic Science Commission, reviewing evidence in a murder case, concluded that a lab analyst for the State who testified for the prosecution did exactly that.
Specifically, this analyst testified definitively regarding who hairs found at the crime scene belonged to, despite the fact that such definiteness is not scientifically supportable” and “misleading,”
She also testified “totally outside the realm of her expertise” when she stated that the evidence suggested that the killer had cleaned up and changed before exiting the house.
She also testified that fibers on a key piece of evidence were consistent with fibers from the trunk of the defendant’s car, despite no record of her ever conducting a fiber comparison.
The link to the article is here. It’s disconcerting to read and reinforces the idea that one needs defense counsel that’s versed in the forensic sciences to minimize one’s chances of having a horror show like this one appear again.