Shortly after Bernie Madoff arrived in prison, at the start of a 150-year sentence, the mastermind behind the largest fraud in financial history was slapped across the face.

Madoff was closely following the way his case was being reported in the media and had gone to the jail’s TV room to watch “60 Minutes.” When he changed the channel—in defiance of the prison’s unwritten rules, he soon learned—another inmate objected and wanted it changed back. There was a scuffle, and then a smack on the cheek.

It was then that Carmine John Persico Jr., the notorious boss of the Colombo crime family, known as “The Snake,” who has been serving his own century-plus sentence at the same prison, intervened.

“Carmine sent his boys over, or his ‘friends,’ rather, to ‘have a talk’ with the guy who delivered the slap,” recounted Steve Fishman, a journalist who has covered Madoff for years. Persico’s men “issued what Madoff called ‘an extraordinarily stern warning,’ and talked it all out. After that, Bernie got to watch” whatever he wanted.

It was the beginning of a beautiful friendship between a pair of notorious, geriatric inmates (Madoff is just shy of 80 and Persico is 83) serving what amounts to life in prison.

According to Fishman, the host of “Ponzi Supernova,” an audio series about the case that features extensive interviews with the jailed Madoff, the mobster and the Ponzi schemer have become “good buddies,” with Persico also acting as both protector and mentor to the disgraced former nonexecutive chairman of the Nasdaq Stock Market.

“It was Carmine who first greeted Bernie when he arrived,” Fishman said. “Carmine sent him shower slippers, tried to make him feel at home. Bernie didn’t know the rules of prison, and that was something Carmine was able to help with.”

The NYPD Organized Crime Task Force suspects that Persico, who served as his own attorney during his criminal trial in 1987, may be linked to multiple murders; nonetheless, Madoff calls him a “very sweet man,” Fishman said. “He talks about how Carmine was visited by his grandchildren, what a tender scene that was, and how gentle he was with them.” Madoff has lamented his own lack of family visits.

The former Wall Street money manager, who once hobnobbed with the deep-pocketed elite, has assembled an unusual fellowship in jail.

“He doesn’t really fit into the prison life, which is very segregated by race and sexual orientation, among other things,” Fishman said. “He moves from group to group. He has social relationships with some of the gay prisoners, the child molesters, the mob guys. It doesn’t matter to him.”

Madoff is incarcerated at the Federal Correctional Complex, in Butner, N.C. It is a medium-security facility, one that is sometimes referred to as “Camp Fluffy” for being relatively comfortable. Madoff has a picture window in his cell, and his door isn’t locked at night. He has access to a computer where he fires off emails, and to a kitchen. The prison yard features both a sweat lodge and a bocce ball court, where Madoff and Persico “hang out,” according to Fishman, who got these details from Madoff himself.

As per the rules of the prison, Madoff has various jobs, including working in the commissary, “kind of like a grocery store clerk,” and mopping the cafeteria floor.

Madoff, who cooked his books to the tune of a $65 billion fraud, “wanted to do something finance related,” Fishman reported. “He volunteered to keep the prison’s books, but the supervisor just laughed. ‘I don’t think so,’ he said.”

To the extent he can, Madoff has remained somewhat active in finance. As Fishman previously told MarketWatch, he has doled out stock advice to other prisoners—or “colleagues,” as he calls them—and bought up the commissary’s supply of Swiss Miss hot chocolate, cornering the market and reselling them for profit.

Mostly, however, he spends his free time reading and talking with his lawyers. Fishman suspects he continues to have contact with Ruth Madoff, his estranged wife, but couldn’t say definitively.

Madoff stays apprised of the fallout from his Ponzi scheme, and even watched the miniseries that was produced about his crimes last year. His only objection to the film, according to Fishman, was a scene in which Richard Dreyfuss—who plays the title role—slaps one of his sons. He took umbrage to that particular characterization.

“People forget, but he really was a good family man,” Fishman said. “He was very careful about how his relationship with his family was portrayed.”

Both of Madoff’s sons died after the fraud was uncovered. Mark Madoff hanged himself on the second anniversary of his father’s arrest, while Andrew Madoff, at the time the last surviving progeny of the swindler, died of lymphoma, a cancer whose return he blamed on the stress of his father’s crimes, having previously been in remission.

Another on-screen account of Madoff is being released, this time with Robert De Niro as Madoff and Michelle Pfeiffer as his wife. The film, The Wizard of Lies, will premiere on HBO on May 20. As reported by The Hollywood Reporter, De Niro didn’t attempt to meet Madoff to inform his performance.

“I always want to meet the person that I’m playing, but I felt, in this case, I was a little wary,” De Niro said, adding he that he was concerned “that that would be a mixed message that I was endorsing him.”

“Bernie thinks he’s come full circle,” Fishman said. “He started as a struggling guy, and now he’s back to making his own bed and ironing his own khakis. His health isn’t great, but he’s a survivor.” In 2016, ABC News reported that Madoff had a “little bit of a heart problem,” citing his lawyer, Ira Sorkin.