Federal agents executed a search warrant Monday morning in Oakland Township, north of Detroit. Authorities were led to that area by a tip from alleged former mobster, Tony Zerilli.
Earlier this year Zerilli told a New York TV station the former Teamsters boss was buried in a field about 20 miles north of where he disappeared.
Hoffa was president of the Teamsters union until 1971. Hoffa was last seen in 1975 outside a Detroit area restaurant. He was declared officially dead in 1982.
The Associated Press contributed to this report.