Jake LaMotta, whose story was told in the 1980 film that won Robert De Niro an Oscar for his performance, was obligated to offer motion picture rights of first refusal to MGM for a 1986 book he co-authored, "Raging Bull II," the document said.

Emails to "Raging Bull II" producer Dahlia Waingort and director Martin Guigui were not immediately returned. LaMotta's agent also did not respond to requests for comment.

The lawsuit, filed on Tuesday in Superior Court in Los Angeles, said LaMotta breached his contract by authorizing RB II Productions to produce a sequel based on the book. The complaint said RB II refused to comply with MGM's demands to halt production, and were associating the sequel with the first film in a way that would "irreparably tarnish" its value.

MGM, which was seeking damages, wanted to block RB II from finishing or releasing the film and was demanding a jury trial.

"Raging Bull," directed by Martin Scorcese, told the story of LaMotta's rise and fall as a boxer, played by De Niro. The American Film Institute listed the film as the fourth-best movie of all time in 2007.

The sequel does not involve Scorcese or De Niro. Actors William Forsythe and Mojean Aria play old and young versions of LaMotta in a cast that also features Ray Wise and Tom Sizemore.

(Reporting By Joseph O'Leary; Editing by Cynthia Johnston and Doina Chiacu)

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