Reporter: Even in the perfect crime, it's the details that can often foil the plot. Like the single shell left behind in randy stone's insurance office. Or a torn up love note in the trash, just a few... See More
Reporter: Even in the perfect crime, it's the details that can often foil the plot. Like the single shell left behind in randy stone's insurance office. Or a torn up love note in the trash, just a few feet from his body. Details police are anxious to hear from the woman who discovered randy's body and seemed to recover from the grief of losing her husband of 19 years in about 19 minutes. Raise the shade on the interrogation room and listen to teresa stone. I saw blood coming out of his ear. And his eye was really -- and i noticed he wasn't breathing. Reporter: Listen as teresa offers up random suspects. Her first statement to the police was, that she had seen kind of a, a dirty looking black guy, walking around the back of their building, and he probably killed him. I think he had a moustache he was pretty tall. Reporter: Or perhaps it was that client. The one who had made a pass at her one day. He's a kansas city cop. Nice. Okay. As for her own whereabouts on the day of the murder, well, teresa had a well-documented, perfectly recalled account, uh, alibi for her day starting with a doctor's appointment. I was supposed to be there at 1:45 to fill out paperwork and my appointment was actually at 2. But the bank was kind of slow so I didn't get there to ten till. I left there about 2:15, so i went shopping at dress barn. I left dress barn around 2:41. Wait a minute. 2:41? You sure it wasn't quarter to 3? Or maybe 2:30? 2:41. Nope. 2:41. No one who wasn't preparing for that, would be able to recite their whereabouts down to the minute, uh, the way teresa stone did. Reporter: Okay, her alibi may be air tight, but what about those other details. Remember, the love note? Well apparently teresa doesn't. Okay. Reporter: Listen as police blind side her with that love note. In the trashcan there was a letter that said happy birthday and all that and it was this big. It was all tore up. She seemed a little taken aback by the question, a little surprised. And she seemed to collect her thoughts. Reporter: So your detectives do what, at that point? The detectives leave the room. And they say, "we're going to go get the note, we'll bring it back to you, maybe that will refresh your memory." Hold on just a second we'll be right back okay. Reporter: But once the detectives were gone and they were out of the room, she, she kind of sat there and she looked at the floor. And then she whispered under her breath -- I forgot about that. Reporter: Did you catch that? Listen again -- I forgot about that. Reporter: She also forgot police were recording her with a hidden camera, when police re-enter the room, teresa tries desperately to recover. Yeah, now I remember and i have had it for a very long time because I kinda had a secret admirer. It was left on my car door. Who is your secret admirer? I don't know who he is. Reporter: And you were-bs detector goes off? Yeah, that's, that's not right. This is not right. Reporter: And this doesn't smell right either -- only a day after her husband's murder, and before he's even buried -- teresa meets with randy's close friend and insurance agent, robert davis, to, you guessed it, grill him about how many zeroes might be on the life insurance check. She seemed distraught. And, and then, it, it was like a switch flipped. And, and she asked if we could go downstairs to their home office, and laid out on the desk were all of these life insurance policies that randy had taken out over the years. So, there wasn't even a death certificate yet, right? No. That's correct. And she was wondering when she was gonna get a check? Right. Right. Reporter: How did that strike you? It struck me as, as odd, given the fact that, it wasn't even 24 hours after randy had been killed. Reporter: Okay, now this might seem like piling on, but you won't believe what else this grieving widow made time to do just after the murder. She's at the tanning salon, making sure that -- Reporter: Wait, she's, she goes to get a tan. She went to the tanning salon, and in addition to maintaining her tan, she talks to the owner about what she could do to have randy's tanning credits transferred to her account. Reporter: Cold. Oh. Uh, that fact really just stuck with me. Reporter: She wanted to look good for the funeral. Maintain her glow. Reporter: And it's not just us. Others notice teresa's strange way of mourning her husband's sudden, violent death. She shares the news with an out of town pastor who says she goes from murder to matter-of-fact in seconds. And, during the conversation, she, um, after we talked about that just for a few moments, she switched, and begun to ask about my wife and my daughter. Reporter: Unnerved, he calls pastor love to tell him what happened. During the conversation, he began to tell me what he had done, during the course of the day, his wife had called him, and told him to go to the hospital and visit a member. And he'd stopped -- he even told me that he stopped to buy a fish sandwich somewhere, and it occurred to me that you're giving me an alibi. Reporter: Two air tight alibis, one from teresa, and the other from randy's closest friend, pastor love. But what would a pastor have to hide? Could his very name be a clue?
This transcript has been automatically generated and may not be 100% accurate.