Transcript for Hiring a Hitman to Murder Your Own Mother?
Hiring a hitman to make someone disappear. It's the stuff of movies, right? Well, not always. The people you're about to meet thought it might be the easiest way out of their rocky relationships. And they thought they could get away with it. We start with one mother who found out she had a price on her head. And you won't believe who tried to take out the hit. Started as a joke. And it got out of hand. And it's cost him everything. Big sky country. Land of open plains. But closed up inside this house, a family with a dark story. Everything changed in the matter of a few hours. It begins on the outskirts of Billings, four years ago, at this used car lot. When an FBI agent stops by to deliver to owner Dana Campbell an unthinkable message. He asked to speak to me out in private. And he said, I hate to be the one to inform you of this, but there's -- we've been notified that there has been a contract put out on your life. A contract on your life. Yeah, yeah. It sounds insane. Not as insane as what comes next. The FBI agent says he has a pretty good idea of who took out the hit. It was her own son, Matthew. They have enough evidence that they are safe in saying that it was my brother who had done that. He had contacted and undercover FBI agent and was making plans to have him kill my mom. The big question -- why? Nikki says she thought their family had an unbreakable poubond. We picked on each other, we picked on my little sister a lot, but at the end of the day, we knew that we had each other. But Matthew's family thinks he wanted something more. His mother's money. My two girls think now maybe if my estate beendy vilded into thirds, maybe he might have even considered, you know, killing them so he could have 100% of it all. Made me question everything that I ever knew about him, you know, was I next? Was my sister next? We'll get back to that in a minute. It turns out, trying to hire someone to make a loved one disappear may be more common than you think. Nice to meet you. Nice to meet you. Meet Julia, who, after a few pleasantries -- You got a little business to discuss. Exactly. Gets right down to it. In one of the most staggering conversations you may ever happen to overhear, she's planning her husband's murder. Said something about a gunshot, how you want me to do it? You want me to shoot him? No, unless you can do it painlessly. That would -- Well, you know, I would prefer to use either a knife or a gun. Whatever is less painful. Do you want an open casket, a closed casket? I don't want an open casket. The stuff she's worried about, like the mess. A gun in the house? It would be messy in the house. She didn't need to worry about at all, because her husband is still alive. You see, the guy she's talking to, on the right-hand there, he is an undercover police officer. So, why not just divorce her husband? Well, there was the insurance money to be had if he were had and then there were his feelings. Divorcing him, I don't have to worry about the judgment of my family, worry about breaking his heart, stuff like this. It's kind of a clean getaway. Not so clean afterall. She's now serving at least five years. Hiring the wrong guy turns out to be a costly, but not uncommon mistake. What they do is, they step to a friend or someone that they knew in their past and what happens, in a vast majority of the time, the person they step to goes to law enforcement -- Really? They get ratted out? I'm confident -- That's what happened to Delia in 2009. These recorded conversations allegedly show her negotiating terms for her husband's murder. It turns out the supposed killer for hire in the driver's seat was also an undercover cop. She was called home by police one day. Thank you for coming. And given the false news that inside, her husband lay dead, murdered. I'm sorry to tell you, ma'am, he's been killed. He's been killed, ma'am. No! And then they got her into an interrogation room. Ill just want to see my husband. She continues to speak as a shocked widow. Remember, as far as she knows, her husband is dead. Then, they tell her, the so-called killer is one of their own men. That's an undercover police officer. We filmed everything you did. Recorded everything that you did. I didn't do anything. Listen -- I didn't do anything. You're going to jail. I didn't do anything, please, I didn't do anything. And finally, they tell her, that her husband is still alive. Your husband is well and alive. Thank god. Oh, yeah, thank god? Can I see him? No, he doesn't want to see you. I just want to see him. Her husband didn't believe her when she got him on the phone. You said you wanted to have me killed. That is not true. How is it not true? How can you believe that? I heard your voice! Mike, I didn't do anything. It doesn't matter, you can hire five Lawyers, they're charging you. They have your choice, your face, everything, on tape. And, indeed, she was sentenced to 20 years. She is now out of jail on house arrest, as her lawyers appeal her conviction. Has murder for hire been around for as long as there's been murder? It's been around forever, because people believe in their sort of naive state that they can step to somebody else, have them come milt the murder. They think, if that guy pulls the trigger, I'm clear. Right. Back in Montana, that's what it seems Matthew Campbell was counting on when someone talked to some friends about taking out a hit on his mother. But again, a problem. Somebody felt that my brother was seriously contemplating doing this, that person went to the department of corrections and basically told on my brother, saying, hey, Matthew Campbell wants to, you know, hire somebody to kill his mother. That's all it took. An undercover FBI agent, posing as a hitman, approached Matthew. He fell for it, was busted and then sentenced to five years in federal prison. On the outside, Dana and her daughters struggle to understand how this could have happened. Matthew tries to explain in letters home. This all blew up in my face and I can't handle it. I need to start living differently, like you have been telling me all along. I finally see where my lifestyle has gotten me. And I have been saved in the name of Jesus Christ. All of this is cold, hard truth and you don't have to believe it but I hope you believe your son. I hope you will somehow talk to me and maybe forgive me some day. Over the last four years, letters like this kept coming. And with them, finally, a measure of forgiveness. The family now believes that Matthew never really intended to kill his mother, and they are waiting for him to come home from prison next month. He wants to move on and put everything past him and we do, too. I think we're going to flourish into the, problem one of the best relationships, I think, I've ever had. Hope springs eternal in big sky country.
This transcript has been automatically generated and may not be 100% accurate.