A defendant in a case that saw more than 30 people charged with gambling-related crimes used mixed martial arts fighters to intimidate customers into paying their debts, according to Federal prosecutors.

Kirill Rapoport, 41, pleaded guilty in August to running illegal poker games in Manhattan as part of $100 million gambling ring that allegedly involved professional poker players, celebrities, and high-powered Wall Street bankers.

Rapoport, according to authorities, was known as a “collector” and used the threat of violence to intimidate players into settling up debts they had run up with the illegal syndicate. He worked closely with partner Arthur Azen, 44, who recently pleaded guilty to money laundering conspiracy and extortionate credit collection.

In order to enhance the risk of not paying up, the pair would allegedly use MMA fighters in order to strike fear into customers. “On Oct. 5, 2012, Federal Bureau of Investigation agents observed the defendant, Azen, and two mixed martial arts fighters go to meet with a player in Azen’s poker games, who based on earlier interceptions appeared to be delinquent in playing Azen’s debts,” wrote prosecutors in a letter to the judge.

During that meeting, authorities, not wanting to see the man injured, were put into a delicate situation and were forced to act quickly. “Out of concern that Rapoport, Azen, and the MMA fighters might physically harm the player and in order not to reveal the ongoing FBI investigation, the FBI arranged for the New York City Police Department to intervene in the meeting by claiming they had received a report of someone smoking marijuana in the area,” prosecutors continued.

The poker player, undoubtedly thankful for the intervention, later confirmed to investigators that he owed around $40,000 in poker debts. The specific MMA fighters were not named in court documents.

Rapoport’s lawyer, Jay Schwitzman, disagreed with authorities’ attempts to have his client serve any significant time in prison, saying what Rapoport did was “hardly different from what you and I do when we play poker.” He also claims his client is being judged unfairly due to his Russian background. “They targeted him because of his ethnicity … He was not part of any Russian mob,” Schwitzman told the New York press.

But prosecutors disagree, asserting, “The defendant’s role in the offense was serious. He was not a dealer or a bartender. His job was to make sure that bettors at Azen’s illegal poker games and bettors of Azen’s sports book paid their debts.”

The FBI’s claim that Rapoport served as a thuggish debt collector were seemingly bolstered by a pair of brass knuckles and an inoperable gun found inside his apartment, “tools of the trade for an enforcer who threatens the use of force to collect debts,” authorities wrote.

Rapoport is only one of many who have already pleaded guilty in order to avoid long jail sentences. Last week, Molly Bloom (pictured), dubbed the “Poker Princess,” pleaded guilty to running illegal high-stakes poker games and will serve up to six months in prison, according to her plea deal.

Various pro poker players were also charged along with Bloom, including Justin Boosted J Smith, Abe Mosseri, and Bill Edler. These were only a few of the high-stakes poker pros invited to exclusive private games arranged by Bloom, which also included celebrities like Tobey Maguire and Ben Affleck.

Rapoport, for his part, faces up to five years in prison, with his plea deal calling for six to 12 months behind bars.

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