Since 2000, at least 24 men who were convicted or charged of murder or rape using a questionable forensic technique known as bite mark analysis have been exonerated. Several of them spent significant time in prison, and some on death row. But on Thursday, a New York judge admitted bite mark analysis evidence in a murder trial, in a case the Associated Press says was a test for the scientifically questionable method.
Reseachers say teeth palates are not unique, and bite marks that do not accurately transfer to skin cannot conclusively be matched to one person. Three studies on bite mark analysis have found significant rates of false identification, from 11 percent at its lowest to 91 percent one study. Even the forensic dentist who testified in favor of the practice said he would only use it if “there was other very strong corroborating evidence.” Others such as University of Buffalo academic Mary Bush, who has published research on bite marks, says the technique should not be admissible in court. Most agree that the technique is questionable at best. But jurors who view scientific evidence with mixed reliability experience what is known as the “C.S.I. effect” and assume it is particularly conclusive.
This case involved the murder of 33-year-old Kristine Yitref, who was found beaten, strangled, and wrapped in garbage bags under a bed in a Manhattan hotel. Clarence Brian Dean admitted to the killing, but says it was in self-defense because Yitref and another man attacked him in a robbery attempt.
The judge’s ruling is less about this particular case, and more about the future admissibility of bite mark evidence. Opponents who believe it is sham science had hoped the case could set a precedent for banning the technique from the courtroom.
“It’s a victory for the Flat Earth Society,” said the Innocence Project’s Chris Fabricant.
Even after DNA evidence revealed the frequency with which shoddy investigative techniques can lead to wrongful convictions, law enforcers and courts have been slow to adapt. Hair sample analysis conducted for years by the FBI has been so discredited that the agency finally recently agreed to review thousands of cases in which the technique was used, but not before near death for several defendants.