with an eerie similarity to the earlier case, dr. hayne testified that he saw what he believed to be bite marks on the girl's body. and the forensic dentist, michael west, testified that those bite marks came from this man, kennedy brewer, the boyfriend of the girl's mother. brewer was convicted and sent to the mississippi state penitentiary to be executed. >> there have been a number of people who were convicted based on bite mark testimony, who were sent to death row or sent to prison for life, and in each of those cases, a whole group of forensic odontologists, forensic dentists, said they were absolutely certain that this was the guy, and they were absolutely wrong. >> bergman: peter neufeld, who represented both brooks and brewer, is a founder of the innocence project, which has helped free hundreds of people who were wrongfully convicted. neufeld says that most of those convictions involved the use of what he calls "invalid" science. >> invalid science meaning it has no basis in fact? >> yeah, like the person who looks at, uh, uh, sc