'Snatching Sinatra' host John Stamos reveals his personal ties to the bizarre kidnapping of Frank Sinatra Jr.

A young John Stamos couldn't imagine anyone being better than Elvis ... until he heard Frank Sinatra.

"I always used to argue with my dad, 'Elvis was the best singer.' [He'd say,] 'No, Sinatra is the best singer,'" Stamos tells Yahoo Entertainment. "My dad was like, 'You listen to Sinatra, and I'll listen to Elvis, and we'll compare.' And I came back, and I said, 'You're right, and he was cool. What'd you think of Elvis?' 'Eh, you know.'"

Later in life, Stamos even took his parents to a Sinatra concert, where they met "Ol' Blue Eyes" himself. (For what it's worth, his mother had told people for years before that, that she happened to run into Sinatra on her honeymoon in Vegas and that he had hit on her. )

Stamos's parents have both died now, but the actor still has a fascination with the '50s and '60s, an era that was filled with what he calls "authentic, true entertainers" who "could do everything well." So, of course, he was interested when the story behind the 1963 kidnapping of Frank Sinatra Jr., the crooner's son, landed in his lap.

"Thirty years ago, I think it was, I was at the Orange County [California] Fair with [musicians] Jan and Dean, who I had a relationship with through the Beach Boys, and Dean [Torrence] turned to me and said, 'Stamos, do you produce? Do you know how to get something made?' I was like, 'Yeah!'" Stamos says. "And I didn't. And he said, 'Well, I got this story. My best friend kidnapped Frank Sinatra Jr. and I have the manuscript that he wrote in prison, and I have the rights to it. Let's try to do something with it."

The result — after years of alternately picking up and dropping the project and trying to find the right place for it — is the 10-part podcast The Grand Scheme: Snatching Sinatra, from Wondery and Spoke Media, that offers the perspective of Barry Keenan, the man behind the kidnapping.

The story is Hollywood legend: Two weeks after the assassination of Sinatra's onetime friend President John F. Kennedy, Keenan and his associates abducted Sinatra's only son from a venue where the 19-year-old was performing in Lake Tahoe. They held him for a $240,000 ransom — that's how much Keenan needed to pay his debts — and turned down the $1 million Sinatra Sr. offered. The younger Sinatra was released after 54 hours, and no one was physically hurt.

Still, it was big news. Keenan and his associates were arrested within days. He was convicted and sent to prison for the rest of his life but ended up spending just four-and-a-half years behind bars. The man behind the plot, who had said God told him to commit the crime via the car radio, was found to have been legally insane at the time of the kidnapping.

"The truth is, especially doing this podcast, because now I have time to really explore his whole life, I mean, we're talking about a mentally ill man, you know, who was addicted to pills and booze and had a very dark, troubled childhood of religion and mental illness that got swept under the carpet because that's what they did in the '40s and '50s," Stamos explains. "You know, he started hearing voices and he told his aunt, who was Catholic — she wasn't a nun but she was really involved in the Catholic Church — and she said, 'Don't tell anybody.' Assimilate. Assimilate. And he spent his whole life not being who he was. And he ran into a lot of hard knocks, and he's always looking for a shortcut. He wanted a seat at the table, and he was gonna do everything he could to get it."

Stamos has spent hours interviewing Keenan, and he's grown somewhat close to him, even though, as the father-of-one says in the first episode, he doesn't take the idea of kidnapping lightly.

"He's like a grandpa to me or something. We've been on this journey for a couple years now, and we've had ups and downs with it. I’m not gonna lie," Stamos says. "You know, I had a big sale on this [lined up], and Barry being Barry, he effed it up. And I said, 'That's it, I'm done.'"

Of course he came back. Stamos knew that it's important to Keenan to tell his story, in part to dispel the theory that Sinatra Jr. — who died in 2016 — or the entertainer himself was in on it.

"He's done a lot of healing," Stamos says. "He's done a lot of work in prison reform with prisoners. He's done a lot of work in the substance abuse area. He's an [Alcoholics Anonymous] guy, has helped a lot of people, so I think he's tried to redeem himself. He's always, through the podcast, he’s talking about the state of grace. He's always trying to reach the state of grace, and I said at the end, ‘Have you reached your state of grace, Barry?' He said, 'Yeah, but I'm still, I'm a work in progress.'"

The Grand Scheme: Snatching Sinatra is available on all major podcast platforms.