the unlikely intruder, the parkers' family friend, bryan capnerhurst. investigators that his friend, bryan, had shot his wife, tammy, in a botched robbery attempt. then brett, in fear for his own life, killed his friend. it looked like self-defense. but sheriff leon lott knew they couldn't close the case without thoroughly checking out brett's story. you know, there was three people there. two of them are dead. so we have to rely on him to explain to us what happened. so we were listening to everything that he was saying. and then we'd go back and check it. andrea canning: investigators went over brett's account, starting with the moment bryan entered the house. before long, something unusual came to their attention. brett told police he was sitting on the downstairs toilet when he heard the shots ring out. but one of the female crime scene investigators noticed this, the toilet seat was up. our csi lieutenant is a female. and she made mention of that. that particularly bothered her. of course, it takes a woman to notice that. right. andrea canning: as t