The confession, said to have been written by Francis (Frank) Sheeran before he died Dec. 14 in a nursing home near Philadelphia, says he flew to Pontiac in a small plane on the day Hoffa disappeared, picked up Hoffa's body from the killers and drove it to a Hamtramck trash incinerator, where it was burned.
But the veracity of the three-page letter is in question.
"It's definitely a forgery. It's not his signature," Sheeran's daughter, Dolores Miller, of West Chester, Pa., told the Detroit Free Press for a story Saturday.
Miller believes the document was created by her father's biographer, John Zeitts of Omaha, Neb., to upstage a book to be published in June by another Sheeran biographer, Charles Brandt, a former Delaware deputy state attorney general.
Zeitts says his book still is in the works.
He said Friday that the confession is genuine and that Sheeran wrote it to clear his conscience about his role in Hoffa's disappearance. Zeitts said Sheeran sent him the confession in November and he forwarded it to Hoffa's daughter, Barbara Crancer, who is a judge in St. Louis.
Crancer gave the letter to the FBI and the Free Press.