Jury tampering, mail fraud and bribery were just a few of the crimes that sent infamous Teamsters' boss Jimmy Hoffa to prison for four years until he was pardoned by President Richard Nixon in 1971. Hoffa had served as president of the International Brotherhood of Teamsters since 1957, and his alleged Mafia ties made him plenty of enemies. Ironically, though, it may have been Hoffa's betrayal of his mobster allies that led to his disappearance.
Two weeks before he vanished on July 20, 1975, Hoffa reportedly stole hundreds of millions of dollars from the Teamsters' pension fund. And, on the day of his disappearance, Hoffa had planned to meet with two well-known Mafia bosses. After piecing together this information, federal investigators had a motive (stolen money) and suspects (mob bosses) but lacked one important piece of evidence: Hoffa's body [source: Time].
Despite multiple FBI searches in the decades that followed, Hoffa's body has never been found. Tips from aging mobsters and anonymous sources have prompted forensic digs in far-flung places as the FBI has attempted to unearth Hoffa's burial site. They've searched beneath the lawn of a private home in Roseville, Michigan, and in 2013 they dug under a concrete slab in a field near Detroit about 20 miles (32 kilometers) from the restaurant where Hoffa was last seen alive [source: Lichterman].
The tips that have trickled in to investigators during the last four decades have contended Hoffa's remains could be found anywhere -- from under an end zone in the now-demolished Giants Stadium in East Rutherford, New Jersey, to a swamp in the Everglades. Another proposed explanation is that Hoffa's body was stuffed into a junkyard car, put through a compactor and then shipped overseas as scrap metal [source: Bump].
Perhaps the real reason Hoffa's body has never been found is far simpler: There is no body. Charles Brandt, who was the longtime lawyer of Teamster official and Mafia hitman Frank "The Irishman" Sheerhan, recounted this particular theory in his book "I Heard You Paint Houses." Brandt retold Sheerhan's deathbed confession, in which Sheerhan says he shot Hoffa and that two "cleaners" then arrived to remove evidence from the crime scene, including Hoffa's body. According to the book, Hoffa's body was incinerated at a nearby funeral parlor soon after his death [source: Brandt].
Although there was never a conviction for Hoffa's suspected murder, more than 30 mobsters have been prosecuted for crimes discovered during Hoffa's disappearance investigation. The exact whereabouts of Hoffa's body may always remain a mystery.