but while he was, linda doing child custody exchanges of jordynn he had met david and rosemary watsonint. >> reporter: rosemary, dave's new wife of two months. >> keep your eye on that name. >> keep your eye on that name, yes. >> what is j.r.'s alibi for the night that linda goes missing? >> on the night that linda went missing, j.r. was with his girlfriend. >> reporter: his new girlfriend. jr was already moving on, he said, but he still seemed concerned about linda. >> jr was very helpful, offering different ideas or people to talk to. >> but i think cynically sometimes, detective, guys inveigle themselves into an investigation when, in fact, they're part of the -- the scheme. >> sure. that-- that could certainly happen. >> reporter: detectives also had more concrete reasons to suspect j.r. >> there was a domestic incident that they were involved in shortly prior to this. >> reporter: just two days before linda disappeared. she had called the pima county sheriff's department. >> she made a report that j.r. had come to her house on curtis and was banging on the windows and banging on

she says, "i don't know." >> that is number one corroboration for when rosemary comes forward later and says that david watsonar, of course. [ laughter ] but, yeah, i have no memory of that at all. her relationship with rosemary was never the same after rosemary started expressing doubts about dave. >> did any of that get to you, jordynn? did you start to turn these ideas around in your head? did she plant a seed? well, is there something to this? >> she really tried. [ laughter ] i'll give her that. but no, knowing my father, i really don't feel could go as far as to kill a woman. >> reporter: don't let the helpful, fire captain image fool you, said the prosecution. dave's training, they said, is exactly why he was capable of killing three women. >> so on one day you may see him saving someone of a heart attack in his emt van. but on other days, there's a different side to him, huh? >> but what does a paramedic do? responds to bloody scenes. they remain calm in such circumstances. and this was david watson's key attribute. >> reporter: that, along with a mountain of other circumstantial evidence. the money c