Behind the glass doors of an unassuming building in Manhattan, staring across a shuttered print shop, a shadowy world stirred, coming alive with the flick of cards, the muted clink of glasses and the quiet hum of a dangerous secret.

Inside one of the three units of the lavish Kip’s Bay apartment, linked to the Bonanno family, one of New York’s notorious five Italian American Mafia clans, an illegal poker operation unfolded, according to the US Attorney’s office.

The elaborate scheme, masterminded by members of four Mafia families in collusion with celebrity athletes, ensnared unsuspecting victims, bleeding them of over $7 million through cunning deception, prosecutors said in the indictment.

Last week, 31 people, including Portland Trail Blazers head coach Chauncey Billups and former NBA player Damon Jones of the Cleveland Cavaliers and Miami Heat, were arrested for allegedly participating in a nationwide conspiracy to rig illegal poker games.

An attorney for Billups denied the allegations. CNN has reached out to Jones’ representatives.

Investigators said 13 members and associates of the four Mafia families supported the games and collected a share of their profits, according to the indictment. Members of the illicit poker scheme at times threatened and resorted to violence when victims failed to pay their debts on time, prosecutors alleged.

FBI Director Kash Patel leads a Thursday news conference to announce arrests tied to illegal sports betting and poker games in New York. Angela Weiss/AFP/Getty Images

Days after the arrest, Lexington Avenue thrummed with ordinary life.