US authorities announced several high-profile arrests on Thursday, including of a star player and a coach in the National Basketball Association (NBA), for alleged illegal sports betting.

Among those in custody are Portland Trail Blazers coach Chauncey Billups and Miami Heat player Terry Rozier, both of whom were reportedly arrested after their teams' games on Wednesday.

The arrests are part of a sweeping investigation into illegal gambling that produced two indictments, the FBI said — one into players who are allegedly faking injuries to influence betting odds, and another involving an illegal poker ring tied to organised crime.

What are the allegations?

The FBI described the allegations as mind-boggling. They include indictments in two major cases involving fraud.

One case, called operation nothing but bet, allegedly involved players using insider information to manipulate wagers. Players would alter their performance to secure betting advantages, leading to profits amounting to tens of thousands.

The second case centers on sophisticated illegal poker rings involving organized crime families in New York. These operations utilized advanced technology, such as X-ray poker tables and pre-marked cards, to cheat unsuspecting players.

Which players have been arrested?

34 defendants have been indicted in these cases, with charges spanning fraud to illegal gambling. Rozier is accused of letting associates know about his planned early exit from a game due to injury.

Billups, among others, faces charges connected to the illegal poker schemes, where players and organized crime figures engaged in violent thefts and laundering through bank and cryptocurrency transactions.

What has the NBA said about the allegations?

The NBA is reviewing the federal indictments and has placed Rozier and Billups on immediate leave. The league maintains a commitment to preserving its integrity amidst these shocking revelations.

Who are New York's notorious 'Five Families'?

The alleged schemes involve four of the Five Families of the New York Mafia: Bonanno, Colombo, Gambino, and Genovese. Despite significant law enforcement efforts in the past, evidence suggests that organized crime remains a significant issue in the realm of illegal gambling.