from dorothy donovan's farmhouse. >> it took us about two and a half months to finally locate gilbert cannon. >> but cannon adamantly denied any involvement in the murder. >> i'm not going to sit here and say that i killed somebody. or that i was even there. >> investigators knew cannon's dna was at the crime scene, but they also took his finger and palmprints for comparison. >> i had suggested that when they took it, to make sure they rolled the palm towards the outside to cover any of the area we may need in question. >> rod hegman compared this fresh print to the print on the handrail in dorothy donovan's house. the result was clear. the print belonged to gilbert cannon, and he was confronted with the evidence against him. >> well, gilbert, one thing i can tell you is you were there. it's impossible for you not to be there, gilbert. we're just telling you, on tape, that is your dna. no ifs, ands or buts. it's no one else's. it's a perfect match. i don't know what you were doing back then. i have no idea. we were hoping to sit down and try to get you here. because gilbert, you know -- >> l