"Anthony Zerilli was reputed to be the underboss of the Detroit organized crime family, so he would have been in the know," Arena said.
Zerilli's criminal record includes a 2002 conviction for conspiracy and extortion. He was sentenced to six years in prison.
Hoffa, Teamsters president from 1957-71, was an acquaintance of mobsters and adversary to federal officials. The day he disappeared, he was supposed to meet with a New Jersey Teamsters boss and a Detroit Mafia captain.
In September, police took soil from a suburban backyard after a tip Hoffa had been buried there. It was just one of many fruitless searches. Previous tips led police to a horse farm northwest of Detroit in 2006, a Detroit home in 2004 and a backyard pool two hours north of the city in 2003.