John Grisham wrote a powerful op-ed, here, today in the L.A Times, discussing causes of wrongful convictions, including flawed forensic evidence. He notes, citing to data that I've collected, that "Of the 330 people exonerated by DNA tests between 1989 and 2015, 71% were convicted based on forensic testimony, much of which was flawed, unreliable, exaggerated or sometimes outright fabricated."
Grisham then discusses a fantastic new book by Radley Balko and Tucker Carringon, “The Cadaver King and the Country Dentist,” that describes how over many years, two experts in Mississippi, testified about forensics to convict people later exonerated.
You can read the testimony in one of those cases, later shown to be false, in the death penalty case of DNA exoneree Kennedy Brewer, here, on my resource website. The analyst concluded that Brewer’s teeth in fact left the marks: “Within reasonable medical certainty, the teeth of Kenneth—un, Mr. Kennedy Brewer inflicted the patterns described on the body” of the victim, and explaining that reasonable medical certainty means “yes, he did” leave the marks.