Transcript for How anti-virus software pioneer John McAfee made his millions

Reporter: There are so many layers to the epic, disturbing story of John Mcafee. Maybe because there are so many John mcafees. John Mcafee is one of the wildest characters you'll ever come across. Reporter: There's Mcafee the party animal. John? Huh? Reporter: Mcafee the silicon valley gazillionare. It is the number one computer threat. Reporter: Mcafee the international fugitive. He's someone that I feel is dangerous. Reporter: Even Mcafee the presidential candidate. Stand with me to protect our freedom. Reporter: Pinning down the truth of Mcafee's life story is never easy because often it is as slippery as he is. He is like teflon, nothing sticks to the man. Reporter: If the name "Mcafee" rings a bell, it should. There's a good chance it's on your home computer screen right now. Yup, he's the guy behind the famous Mcafee antivirus software. When we say we are going to talk tomorrow, does that mean face to face? I first crossed paths with Mcafee in 2012, when he'd become even more famous south of the border. He was on the run, and would only talk to me by phone. You may not think you are being followed but I can assure you, you are. Reporter: Hello? Anybody home? But I wasn't chasing him around Latin America because of a cyber crime. This was a real life homicide, allegations that he murdered fellow American Greg Faull. We begin with that software millionaire on the run suspected of murder. Reporter: Police wanted to question Mcafee about the murder, but he didn't want to answer. He dodged authorities all the way back to the U.S. Where he has been ever since, never charged with a crime. The Pandora's box has been opened. Reporter: But what makes this story even stranger is John Mcafee's latest incarnation. Our computers are no longer back home in the office, they are in our hands. Reporter: These days he's re-emerged as a prophet of digital doom and his apocalyptic warnings about today's cyber threats attract plenty of eyeballs both in person, and on TV. We're being spied on by our government. Reporter: Even with all that attention, what he hasn't done since returning home is a no holds barred interview on every aspect of his past. But now, after more than four years, I'm about to get my chance. I admit, I've heard so many things about him. He's erratic, he's a high-tech prince of darkness, he's just plain dangerous, that I'm nervous. I've been warned about John Mcafee. So I'm keeping my second cell phone and my credit cards here at the hotel so they don't get hacked. I drive on to our meeting place, a parking lot in rural Tennessee, where Mcafee greets me like a southern gentleman. How you doing, sir? Good to see you. Reporter: How are you? We talk a bit and head off in his tanklike truck. If I have to put up with people like you then I'm going to have fun doing it. Reporter: To him, reporters are just like a ball of twine to a cat, something to play with until he gets bored. We arrive at a quiet suburban downtown for a casual lunch at this Mexican restaurant. You like Mexican food? Reporter: Yeah, I like Mexican food. Sure. You said you grew up in town like this in Virginia, right? Between bites of chips and salsa, and beers for Mcafee, we talked about his troubled childhood. One of things that was not idyllic there was your father. You've said that he was a raging alcoholic and that he was abusive to you and to your mother. Nobody has an ideal life, even children. Hedyed when you were 15? 15. Reporter: He shot himself? Yeah. People always look to the past to explain the present. It doesn't work that way. Reporter: The present for Mcafee -- this upscale but hardly lavish spread. He shares it with his new wife Janis, his everpresent bodyguard, and his dogs. As we sit down inside, fortified by a glass of expensive scotch, Mcafee continues with his life story, saying that despite being a lazy kid, he always got straight "a"s. Math came easy to me. I've never studied. I just did what I felt I should do. Reporter: In college, Mcafee says he began peddling a product he knew he could sell, cocaine. It's interesting that drug dealing was really your first foray into entrepreneurship? Yeah. It's everything, it's salesmanship. Reporter: Then came the dawn of the go-go '80s. ??? big hair, even bigger shoulder pads, pac man fever. As the home computer revolution kicked in, Mcafee, now working as a programmer, was among the first to identify its perils and a potential profit. A computer virus is a programmer written by a hacker with a unique purpose, and that purpose is to multiply and to live. I was figuring out, oh yeah, I can stop this here, I could stop this here, I can actually remove this thing. And wrote a program in a day and a half. Reporter: So Mcafee antivirus was created in a day and a half? Yes. Reporter: And how well did it work? 4 million people were using it within a month. Five years later over half the fortune 500 companies in the country had begun using it. That's how important it became to their business and to keeping their computers safe. Reporter: In no time, the software bad boy amassed a large fortune. But as Mcafee admits he gets bored easily, so after a few years he cashed out. You made $100 million, let's say, for selling Mcafee, right? That's what they say. Reporter: How much did you make? Much more. Reporter: What did you do with the money? I wasted it, like everybody who has money. Reporter: He built nine homes, filled them with expensive art and furniture, bought a fleet of antique cars. Is that love? Isn't it selfishness? Isn't it all about you? Reporter: His next chapter, creating a yoga retreat in Colorado, reinventing himself as a new age guru bestowing his eternal wisdom on his guests. It's all about need and jealousy is all about the fear of losing all of these things which you have attained. Reporter: But Mcafee says his zen was disturbed by a constant wave of what he calls frivolous lawsuits. Tonight on "Nightline," losing a fortune. Reporter: So after the financial crash, in 2009 Mcafee let it be known he had lost most of his money. How to kiss nearly $100 million dollars good-bye. Sometimes a little bit of pain is necessary to see and understand the true circumstances of your life. Reporter: "Nightline" covered this auction on Mcafee's ranch where everything, including his beloved airplanes, winnebagos, exotic art collection, even the gold elephant and dinosaur skull went on the block. Starting off at $1 million. Reporter: Mcafee now claims he it was all a charade, a ruse. He was just trying to look broke so people would stop suing him. No, I didn't lose my fortune. I'm not that stupid. Reporter: Whatever the case, one part of that report is indisputable. Now Mcafee plans to take his remaining handful of millions and head to Central America.

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