robert messer. >> 20-year-old robert messer's fingerprints were on file. >> lo and behold, there was mr. messer's prints on some of the items in the trunk of denise's car. >> when police arrested messer, he too denied any involvement in the murder. >> robert messer told me, i didn't kill her. i'll tell you what happened. i was there. >> messer said he did nothing. but that caballero and brown were both involved. messer said he was in caballero's living room when caballero and brown raped and murdered denise o'neill in the bedroom. >> i sat there with my fingers in my ears. the tv was up loud. i could barely hear the tv but i heard her screaming. i heard her screaming. >> all three men were charged with first degree murder. but when dna results came back only one of the three, luis caballero, was tied to the sexual assault. based on the forensic evidence and witness interrogations, investigators believe that caballero planned the attack on an afternoon when denise was doing her laundry. when no one was around. he grabbed her and forced her into his apartment. and with isac brown's help