these are defensive wounds. >> no witnesses, no weapon, nothing left behind but a stranger's dna. >> we no longer have some accidental death. this was a homicide. >> they had no suspect, but for years her mother kept fighting to find bonnie's killer. >> bonnie's mother continues her own crusade. >> then after more than a decade of searching, a phone call. >> they got information there was a match. >> can we get a conviction on just the dna? >> and there was something else, something about bonnie herself. >> it was almost like she knew something. >> keith morrison with "justice for bonnie." >> good evening and welcome to "dateline."