Transcript for John McAfee denies any involvement in neighbor's murder

Reporter: In his rural Tennessee outpost, John Mcafee has a new set of dogs, but he's pretty much given up the trappings of his old millionaire lifestyle. For a guy who, in Belize, had all of these toys, boats, sailboats, this is a quaint suburban lifestyle. The things you think you own, own you. Reporter: But even here he still has an armed bodyguard anywhere he goes. People ask me, you think you'll ever need to use it? I say no, but you only get one shot. Reporter: And a private arsenal at the ready inside the house. I don't even know what this is. I'm not going to tell you what that is, because that's the newest weapon available. We're not going to tell you anything. Reporter: Is it a real gun, though? Believe me, it's a Real gun. Reporter: Do you have a fascination with guns? I have no fascination with guns. I have a fascination with survival. Reporter: When you held that gun up to your head in that picture, were you thinking about your father, who took his own life? Oh, Christ almighty, my friend, are you losing your mind? Are you? No. Reporter: Mcafee and his wife claim that for the past four years they've been followed wherever they go. We had been chased for days, and you could see the same cars and trucks over, and over, and over. Reporter: Are you paranoid? If I were, would I know?? He makes up a lot of preposterous statements. Reporter: Paranoia or not, there's no doubt at all that filmmaker Nanette Burstein has been hot on his trail. When her film "Gringo" was released last year it caused shockwaves, thanks to interviews with Mcafee's ex-employees who talk about his bizarre activities. When it specifically comes to Faull's murder -- you think found the smoke to the fire of the Greg Faull murder. Yes, I did. Reporter: This man, Mcafee's beachfront caretaker named cassian, alleges his boss paid to have it done. It starts the night the dogs were poisoned. The following morning, sometime around 9:00, John calls me. He said, take this money, $5,000, and go put it in this guy's account. Reporter: Cassian says the man who got that money called him late the night of the murder to come pick him up. I saw him coming out of the bushes. It was like 600 feet from Greg's house. Then I realized that this $5,000 was for him to do that. To do what? To kill the guy. To kill the guy. Reporter: The supposed killer denied both cassian's story, and that he killed Faull, but it seems like a damning accusation. There was some very convincing testimony, very convincing evidence that I had not seen before that makes me believe that there could be an inveigation reopened. Reporter: This documentary has brought what appears to be new evidence -- Mcafee laughs it off. Everyone who went on TV called me, and said th offered me $12,000, I said take it. Reporter: Mcafee accuses Burstein of paying cassian and others in the film to tell lies. He got $12,000, but he was smart enough to make up a story that no one would believe except Nanette because she is the most naive woman I have ever met. Reporter: Mcafee posted videos online in which cassian, and others, take back what they said. John had nothing to do with that murder. What I told you, Nanette, was a fabrication to earn what you offered to pay me. Reporter: Those are some serious accusations. They are. Reporter: Burstein denies paying for any interviews, though she says she did pay what she calls a nominal fee for some photos. She says Mcafee was the only one who paid for a story, pressuring cassian to recant. I called him and said, listen, why did you do this, and he said someone showed up at my house that works for John, and they offered me thousands of dollars to say this. People in Belize understand why cassian and the others have to say that they made it all up, because their lives could possibly be in danger. Reporter: Both cassian and Mcafee deny that he was paid off to change his story. Let me make this perfectly clear, I had nothing to do with the murder of Gregory Faull. You are asking the most ridiculous things. Reporter: You have to admit that it's not ridiculous that nine of your dogs, your beloved dogs, are poisoned. By the government -- Reporter: That would make a man that loves animals absolutely irate. Right, now, if I -- Reporter: It would be enough to make a man, who loves his dogs, willing to kill, some would say. Does this man look like he would be stupid enough to kill whoever was responsible? Reporter: I don't know if he would be stupid enough. The night after? Because this is a logical question. Reporter: Did you order a hit on him? Of course not. Please. I am sick of Belize. We are finished with Belize. Reporter: That is your choice, but we're not. I have a couple more questions about Belize. As we ratcheted up the pressure on Mcafee about Belize, he started to walk out on our main interview. You're walking out? Yes, because you have not kept your Word. Reporter: There had been no preconditions to the interview, and Mcafee quickly calmed down, and sat down.

This transcript has been automatically generated and may not be 100% accurate.