The final resting place of teamster official Jimmy Hoffa has remained a mystery for nearly 40 years. Various theories and speculative musings have kept the mystery alive all this time. Not a year goes by that someone doesn’t claim to know where the mob-connected union leader is buried (or interred, or mixed into cement, ect…).

This week, the FBI has taken one of these tips seriously enough to commence digging operations near a small town north of Detroit. According to the Detroit Free Press, the FBI and Oakland County Sheriff’s Office are surveying a vacant field in Oakland Township, Michigan. The site is where Detroit mob boss Tony Zerilli claimed Hoffa is buried back in January. The FBI told the Free Press that Zerilli’s claims could be credible, based on his family connections at the time of Hoffa’s disappearance.

Hoffa disappeared on July 30, 1975. His car was found in the parking lot of the Manchus Red Fox Restaurant in Bloomfield Township, a suburb of Detroit. He had allegedly gone to the restaurant to visit mafia leaders, who were later found not to have been at the restaurant. Though Hoffa was declared legally dead in 1982, the FBI has continued to investigate his disappearance.

(via Detroit Free Press)