Charles Brandt, a former homicide prosecutor whose 2004 true-crime best seller, “I Heard You Paint Houses,” was adapted by Martin Scorsese into “The Irishman,” starring Robert De Niro as the Mafia hit man who killed the ex-Teamster boss Jimmy Hoffa, died on Oct. 22 in Wilmington, Del. He was 82.

The death, at a hospice facility, was confirmed by his brother-in-law, Gary Goldsmith, who did not specify a cause.

Mr. Brandt’s book purported to solve the mystery of Mr. Hoffa’s disappearance and presumed death in 1975. He identified Hoffa’s killer as Frank Sheeran, a World War II veteran and truck driver who had been recruited into the underworld by the Mafia boss Russell Bufalino.

Mr. Sheeran did some enforcement work for Mr. Bufalino, who introduced him to Mr. Hoffa, who said to Mr. Sheeran, “I heard you paint houses.” That was apparently mob slang for killing people — with the word “paint” meaning blood.

In a series of interviews over five years, Mr. Sheeran told Mr. Brandt that he had been ordered to kill Mr. Hoffa, who had just been released from prison and was trying to regain power in the underworld.

Mr. Sheeran recalled luring him to a house in Detroit for a supposed meeting with organized crime figures.