>> reporter: throughout the interview, david repeatedly denied having any involvement in kay's murder or being a part of some plot to have her killed. >> never once has there been any kind of insinuation, not even insinuating that i would ever want anything to happen to her. >> reporr: as for those repeated calls from california the morning of the murder, david insisted he was genuinely concerned about kay. >> iit normal for you to call her that early in the morning, call kay, you know, 7:00 in the morning? >> always. i always call her 'cause i, like, talked to derek before he went to school. i started gettin' worried. i thought maybe she was in an accident or somethin' out on columbia road or somethin'. >> reporter: edmunds started thinking david was telling the truth. so he changed course and asked david whether he thought becky had it in her to mastermind kay's murder. >> deep down inside, do you think she could do this? >> i thought never. i never thought that she would be like orchestrator or set something up like this. i did not think that.