A 19-year-old chess grandmaster is seeking $100 million in a federal lawsuit alleging a rival chess player and others destroyed his career with false accusations of cheating, elevating a controversy that has roiled the chess world since September.

Hans Niemann filed the lawsuit Thursday in U.S. District Court in St. Louis against chess world champion Magnus Carlsen, who has suggested Niemann cheated during his upset win over Carlsen at the Sinquefield Cup tournament in St. Louis.

Niemann is seeking damages from Carlsen; Carlsens company Play Magnus Group; online chess site Chess.com; Hikaru Nakamura, an American grandmaster who is an influential streaming partner on Chess.com; and Chess.com executive Danny Rensch.

It alleges the defendants worked together to defame and libel Niemann after his Sinquefield Cup win.

Despite the falsity of the Defendants accusations, Defendants malicious defamation and unlawful collusion has, by design, destroyed Niemanns remarkable career in its prime and ruined his life, according to the lawsuit.

Niemann says tournaments have banned him, matches have been canceled and reputable chess schools wont hire him over the false accusations.

The lawsuit contends Carlsen is seeking to preserve his status as the King of Chess and to complete a deal with Chess.com to acquire Play Magnus for nearly $83 million.