BOCA RATON, Fla. (AP) — Charles "Chuckie" O'Brien, a longtime associate of Teamsters boss Jimmy Hoffa who became a leading suspect in the labor leader's disappearance and later was portrayed in the Martin Scorsese film "The Irishman," has died.

O'Brien's stepson, Harvard Law School professor Jack Goldsmith, said in a blog post that O'Brien died Thursday in Boca Raton, Florida, from what appeared to be a heart attack. He was 86.

O'Brien was a constant companion to Hoffa in the decades when the labor leader developed the Teamsters into one of the largest and most powerful unions in the nation in...