Flawed Dental Evidence Leads to Overturning of 1997 Murder Conviction in California

The California Supreme Court has overturned a 1997 murder conviction after finding the expert testimony of a prominent dentist was faulty and the bite-mark evidence shown to jurors was unreliable.

The ruling means San Bernardino resident William “Bill” Richards could go free two decades after being arrested for the 1993 murder of his wife Pamela.

On Aug. 10, 1993, Pamela Richards was manually strangled and severely beaten with two fist-sized rocks. Her skull was crushed with a concrete steppingstone.

Bill Richards told police he arrived from work just after midnight to his unusually dark home. Searching for his wife, he eventually stumbled across her half-naked body, finding her head bashed in and her brain exposed.

He called 911 and a police officer arrived at 12:32 a.m., followed by homicide detectives at 3:15 a.m. However, police failed to effectively secure the crime scene, allowing dogs to roam freely and potentially contaminate evidence.

Police were unable to place anyone else at the scene of the crime, and eventually charged Bill Richards with his wife’s murder. The heart of their case was the prosecution’s assertion that Richards was the only one with the opportunity to commit the crime.

The prosecution also presented a blue thread found under Pamela Richards’ fingernail, which prosecutors believed came from her husband’s shirt.

However, the final piece of key evidence came from a well-respected dentist.

Pamela Richards had a bite mark on her hand, and forensic dentist Norman “Skip” Sperber testified at the time that based on Bill Richards’ “highly unique lower dentition” the bite mark was likely made by Bill Richards’ teeth. In fact, Sperber said Richard’s unique dental pattern and under-erupted canine was probably present in only 1 or 2 patients out of 100.

Bill Richards was convicted in 1997 and sentenced to life in prison.

However, in 2008, Sperber recanted his testimony, saying his 1-2% figure was based only on personal experience and wasn’t a scientifically rigorous statistic. Further, dentists hired by the defense found angular distortions in the photograph of the “bite” mark. Once those distortions were accounted for, neither Sperber nor the defense experts could even say for sure that the mark came from a human, much less one specific person.

This new development spurred a state appeal and late last month the state’s Supreme Court unanimously agreed the testimony qualified as “false evidence” and the bite-mark evidence was crucial to the case. Aside from the alleged bite mark, the court found only circumstantial evidence suggested Richards was the culprit.

The ruling, two decades after the conviction, was the first test of California’s “junk-science” statute, which was passed in 2015 to make it easier to overturn convictions based on testimony later recanted by expert witnesses.

Now, prosecutors are left to decide whether to bring the case to trial again. In the meantime, Richards will be released from state prison and moved to local law enforcement custody in San Bernardino County.