NEW YORK — It is a case teaming with colorful characters: a reputed Russian mob boss once accused in an Olympic scandal, a wealthy art world impresario who hung out with actor Leonardo DiCaprio, and a woman named Molly Bloom who gained a celebrity following by hosting them at high-stakes poker games.
US authorities allege all had roles in a sprawling scheme by two related Russian-American organized crime enterprises. Prosecutors say in recent years the operations laundered at least $100 million in illegal gambling proceeds through hundreds of bank accounts and shell companies in Cyprus and the United States.
The case against more than 30 defendants, announced last week by federal prosecutors in Manhattan, illustrates the insatiable appetite for sports betting around the globe — and the enormous potential for illicit profits.
The steep rise in wealth among the upper class in the former Soviet Union has driven that potential to new heights, said Mark Galeotti, a Russian organized crime expert at New York University.
‘‘We’re seeing higher-rolling businessmen involved in these types of cases,’’ Galeotti said. The high rollers’ bookies are left with the problem ‘‘of trying to figure out what to do with suitcases full of cash, and that leads to the money laundering,’’ he said.
The tentacles of the scheme reached to Trump Tower, the Fifth Avenue high-rise where prosecutors say a US ringleader lived in an apartment one floor below Donald Trump’s own place. There, he oversaw a network of Internet sites that formed ‘‘the world’s largest sports book’’ that catered ‘‘almost exclusively to oligarchs living in the Ukraine and the Russian Federation,’’ prosecutors said.
On one of the thousands of conversations intercepted on the defendants’ cellphones, the leader could be heard warning a customer who owed money that ‘‘he should be careful, lest he be tortured or found underground,’’ a prosecutor said.
The ring paid Alimzhan Tokhtakhounov — already under indictment in a separate US case accusing him of bribing Olympic figure skating judges at the 2002 Winter Olympics in Salt Lake City — $20 million in gambling proceeds in a two-month period alone, court papers said.
In another transaction in late 2010, the same man wired $3 million from a Cyprus bank account to another account in the United States, the papers said.
The new indictment naming Tokhtakhounov called him a ‘‘vor’’ — translated “thief’’ — and comparable to a Mafia godfather. His role, the court papers allege, was to use his ‘‘substantial influence in the criminal underworld to resolve disputes among criminals.’’
US investigators following the trans-Atlantic money trail also uncovered a related scheme involving a Manhattan art gallery and high-stakes illegal card games in New York City — one played in the Plaza Hotel. The games attracted professional athletes, Hollywood luminaries, and business executives, some who ran up debts in the hundreds of thousands of dollars.
Authorities did not name the players. But press reports linked actors such as DiCaprio and Ben Affleck to the games run in Los Angeles by Bloom. And DiCaprio was photographed with Hillel ‘‘Helly’’ Nahmad, a friend charged in the case.
A spokesman for both film stars declined to comment on whether they had cooperated with authorities. Playing poker is not a crime, but it is illegal to profit by promoting it.
Nahmad, 35, comes from an art-dealing family whose collection includes 300 Picassos worth $900 million, according to Forbes.
FBI agents Tuesday raided his gallery on Madison Avenue — a seller of works by Chagall, Dali, Degas, Monet, Matisse, and Warhol — and seized computers and records.
Prosecutors allege that, along with laundering cash, Nahmad committed fraud by trying to sell a piece of art for $300,000 that was worth at least $50,000 less. He also wired more than $1 million from his father’s bank account in Switzerland to a US bank account to finance gambling, prosecutor said.
Bloom, 34, moved her poker games from Los Angeles to New York to cater to Wall Street financiers, prosecutors said. But she reportedly went back to the West Coast after two men — described as ‘‘Eastern European thugs’’ in one report — roughed her up at her Upper West Side apartment. Her lawyer at the time said she decided give up poker for her own safety.
Both Nahmad and Bloom pleaded not guilty Friday in a federal courtroom in Manhattan that could barely accommodate the defendants. She entered her plea from a back row. She and Nahmad are free on bail.
‘‘We do not believe Mr. Nahmad knowingly violated the law,’’ said his attorneys, Benjamin Brafman and Paul Shechtman. Bloom’s attorney declined to comment.
A judge has scheduled a trial for the summer of 2014.