no alibi for the night of the crime. >> i've never been so sure in my life as a detective that doug desilva the right person. >> desilva was arrested and charged with the attempted murder of kaye robinson. >> he said, "tell her i'm sorry. i didn't mean to do it. i remember going there, but i don't remember stabbing her." to me, that's a confession. >> but then came the bad news. desilva's fingerprints did not match the prints taken from the blue plastic glass in kaye's home. >> the fact we didn't get any fingerprints that matched doug desilva's from the scene never led us to believe that he wasn't the suspect. because a lot of times, we don't find any fingerprints. >> and perhaps the worst piece of news was that desilva's dna profile did not match the evidence collected from kaye robinson's rape kit. >> dna evidence conclusively ruled out doug desilva as being involved in the crime. it was almost like being struck in the head by a 2 x 4. >> we were extremely shocked. it was like someone had punched you in the stomach. >> this was devastating. the investigators, the prosecutors in the case w