A federal judge revoked bail for Richard Luthmann, the Staten Island attorney known for challenging a courtroom adversary to “trial by combat” who is being indicted for his role in a scrap metal fraud scheme, for allegedly sending a threatening letter to a potential witness in his case.

In a hearing on Wednesday before U.S. District Judge Jack Weinstein of the Eastern District of New York, Luthmann’s attorneys said the contents of the letter were inspired by their client’s love of the hit HBO series “Game of Thrones,” were not intended to be threatening and dealt mostly with returning clothing and computers to Luthmann.