Labor union leader Jimmy Hoffa's disappearance has left authorities puzzled for nearly 40 years. Today, investigators begin digging up a field in Michigan, hoping to find Hoffa's remains.

The dig was initiated after a tip from a former mob boss. Earlier this year, 85-year-old mobster Tony Zerilli claimed that Hoffa's remains were buried in an empty lot in northern Oakland Township, about 20 miles from the Detroit-area restaurant where Hoffa was last spotted in July 1975. Supposed plans to eventually relocate the remains never came to fruition. Officials find some credibility in Zerilli due to the fact that his father, Joseph Zerilli, was the Detroit mob boss at the time of Hoffa's disappearance.

Officials are hopeful that this dig will allow them to find the body of the former Teamsters boss. Oakland County Sheriff Michael Bouchard said today, "It's my fondest hope that we can give... closure not just to the Hoffa family, but also to the community and stop tearing that scab off with every new lead and bring some conclusion."

Hoffa was kidnapped in the restaurant's parking lot, where he was believed to have been meeting with mob leaders Anthony Provenzano and Anthony Giacalone. At the time, the FBI linked his disappearance to his efforts to regain influence over the Teamsters and to the mob's hand over the union's pension funds. Despite an outpouring of tips, Hoffa's remains never turned up, and no one was ever charged for his disappearance. He was declared legally dead on July 30, 1982.

Over the years, many have theorized over Hoffa's death and remains. One such theory suggested that Hoffa's body was incinerated in a trash compactor in Michigan before being relocated and buried in an unknown location in Florida.

The property authorities are currently digging up was once owned by Jack Tocco, Zerilli's cousin.