PHOTO: This July 26, 1959 file photo shows Teamsters Union president Jimmy Hoffa in Washington.
VIDEO: Former Mafia boss Tony Zarilli offers tip to the FBI about the location of Jimmy Hoffa's remains.
PHOTO: Investigators look over the scene in Oakland Township, Mich., June 17, 2013, where officials search for the remains of Teamsters union president Jimmy Hoffa who disappeared from a Detroit-area restaurant in 1975.
PHOTO: American labor leader Jimmy Hoffa is seen during his trial in Chicago in 1964.
PHOTO: Famous missing Americans Jimmy Hoffa, Amelia Earhart, and DB Cooper.
PHOTO: People photograph a driveway in Roseville, Mich. that a tipster said could be the final resting place of missing Teamsters leader Jimmy Hoffa.
PHOTO: People photograph the driveway in Roseville, Mich., Sept. 26, 2012 where police plan to take soil samples f Friday after a tipster said it could be the final resting place of missing Teamsters leader Jimmy Hoffa.