SACRAMENTO, Calif. - At least 24 men convicted or charged with murder or rape based on bite marks on the flesh of victims have been exonerated since 2000, many after spending more than a decade in prison.
A judge's ruling later this month in New York could help end the practice for good and a California case is drawing attention in another way.
William Richards San Bernardino was convicted in 1997 of murder in his wife's 1993 death after two trials resulted in hung juries. Dr. Norman Sperber testified for the prosecution that a suspected bite mark on Pam Richards' body was consistent with a rare abnormality in William Richards' teeth.
In 2009 Sperber recanted his testimony and said he had been wrong but the prosecution appealed, and the California Supreme Court ruled in December that Richards had failed to prove his innocence.
Since April 27, Richards' attorneys have been on what they call an "innocence march" from San Diego to Sacramento, to deliver a request for clemency to Gov. Jerry Brown and raise awareness about wrongful convictions.