The Irishman: No One Knows For Sure What Happened to Jimmy Hoffa, but Here's What People Think

Frank Sheeran was a World War II veteran who first found his way into organized crime after he was discharged from the army in 1945. Though by day he worked as a truck driver, by night he made extra money as a hitman. Eventually he grew to be a close associate of Mafia boss Russell Bufalino, head of the Bufalino crime family, who acted as a mentor for Sheeran.

With Bufalino's help, Sheeran began working with Jimmy Hoffa, an infamous labor union leader who then served as the president of the International Brotherhood of Teamsters, a union that historically suffered from corruption and control by organized crime. Sheeran earned Hoffa's trust and eventually became a top Teamsters Union official, while still acting as the Bufalino crime family hitman and top aide to Bufalino himself.

Initially, Hoffa was very popular. Under Hoffa, the union won substantial gains for its members, bringing all truck drivers under a single collective bargaining agreement, the National Master Freight Agreement, and his achievements won Hoffa both esteem and power. Unfortunately, Hoffa's crimes caught up with him, and he was sentenced to 13 years in 1967 for jury tampering, attempted bribery, and fraud, but just four years later, he was pardoned by President Nixon with one catch: he had to agree to resign as union president and not participate in union activities until 1980.

Unsurprisingly, Hoffa found that he couldn't stay away. He tried to initiate a comeback at the local level with Local 299 in Detroit — where he still had associates and influence — and eventually planned to run again for presidency of the union. Due to Hoffa's eagerness, Bufalino was worried that Hoffa would be willing to trade information to the Justice Department in exchange for lifting the restrictions put on him by Nixon. To keep him quiet, Bufalino ordered the hit on Hoffa, and he purportedly turned to Sheeran to do the job.

According to what Sheeran told Charles Brandt, the author of I Heard You Paint Houses, he and a few other associates picked Hoffa up at a restaurant called the Red Fox on July 30, 1975, under the guise of bringing him to a meeting at a Detroit house. When they arrived at the house and Hoffa saw that it was empty, he was immediately suspicious and tried to flee. In the book, Sheeran says he shot his friend twice in the back of the head and that he did not suffer. Soon after, Sheeran and his associates brought Hoffa's body to a crematorium.

Though Sheeran later served 13 years of a 32-year prison sentence, it was for labor racketeering, not for Hoffa's death. Despite all the witnesses who testified, there wasn't enough evidence for the grand jury to make an indictment. It wasn't even until Sheeran was on his deathbed in 2003 (the year before Brandt published his book) that he finally confessed to killing Hoffa to three priests, as well as to Brandt.

Not everyone believes Sheeran's deathbed confession. Dan Moldea, author of 1978's The Hoffa Wars (which tells the story of Hoffa's rise and fall in the Teamsters Union), insists that Sheeran did not kill Hoffa. Moldea agrees that Sheeran lured Hoffa into his car from the Red Fox, but he believes that the murder was actually committed by Salvatore "Sally Bugs" Briguglio, a member of the Genovese crime family.

According to Moldea, Hoffa was most likely driven to a farm owned by Rolland McMaster, a former Hoffa associate, where he was murdered by Briguglio. He believes Hoffa's body was then put in a 55-gallon drum and shipped to a mob-owned landfill on the Hackensack River in New Jersey.

Though 17,000 Hoffa case documents were released almost 30 years ago after the FBI was sued, Moldea said that the government redacted the majority of the files, and he is still fighting for the unredacted files to be made public. "We have a famous American . . . who vanished from a public place in broad daylight," Moldea told Fox News. "We need to know what happened."