call now. >>> the military community at fort lewis in washington state reacted to dorothy davis' suicideh shock and grief. the coroner ruled dorothy's death a suicide. but many were skeptical. including a woman who was with corporal davis the night dorothy died. the witness said that chris left the bar to call dorothy from a pay phone in the lobby. she said, she too went out to the lobby a short time later and chris davis wasn't there. he returned 20 minutes later. >> witness told us at this point that corporal davis was red faced and appeared to be out of breath. he was no longer wearing a jacket he was wearing earlier. >> so, where was chris' jacket? investigators saw it in the photos taken of the scene the night of dorothy's death, hanging on the doorknob of the couple's bedroom. i thought, he oh, my god, look, here's the maroon jacket. but it's important. it's not thrown -- it's not dropped. and the person who comes in and finds their wife lying there, perhaps mortally wounded is not going to take his jacket off nice and neat and hang it up on the doorknob. >> was it possible that ch

could save. >>> investigators wanted to know who had licked and closed the envelopes that held dorothy davisnotes. to find out, scientists needed dorothy's dna for comparison. unfortunately her body had already been cremated so they had to reconstruct her dna profile by analyzing the dna from both her parents and her two children. >> her dna type was determined by cross-referencing the possible types that she could have received from both the mother and the father and looking at the resulting types that she donated to both of her children. >> chris' dna profile was on file as part of his military records. scientists cut a small piece of envelope flap, put it into a solution that dissolved everything but the human cells and performed a pcr dna test. the results? the dna test revealed that chris had licked the envelope flap. >> placed that letter in the envelope and sealed it himself. that is the only reason his saliva was on those envelopes. dorothy had no intention of committing suicide. those letters were a cry for help. and that chris used those letters to pad his scheme to murder his wife