>> i think probably anna cox was, really. >> reporter: anna cox, a blood-stain expert, testified that kevin's blood was not only on his mother but also on her bed cover. >> if he says he wasn't in the room, does your scientific finding deny that premise? >> yes. >> there's no question in your mind. science tells you he was in that room. >> yes. you had to be right next to the comforter. >> reporter: to the prosecutor, it was a home run, confirming bill kyne's story -- that he opened the door and saw kevin straddling the bed on top of diane. and, loughery argued, kevin's blood at the crime scene had to get there during a struggle with his mother or when bill pulled him off her. >> it put the lie to his story that he was not in there. >> there's no innocent explanation. >> reporter: and his broken glasses had been found in the bedroom, along with birkenstock sandals, one inside the room, one by the door. >> he was adamant they were not his sandals. >> yes. >> he never wore them. >> he actually says, "i've never seen them before." >> but what did science find? >> his dna was on 'em. so,