OAKLAND TOWNSHIP, Mich. -- The excavation of a rural field in suburban Detroit has failed to turn up the remains of former Teamsters union leader Jimmy Hoffa, the FBI announced Wednesday, adding another unsuccessful chapter to a nearly 40-year-old mystery.
Authorities stopped the dig after just a few hours on the third day.
"We did not uncover any evidence relevant to the investigation on James Hoffa," said Robert Foley, head of the FBI in Detroit.
"I am very confident of our result here after two-days-plus of diligent effort," he said. "As of this point, we'll be closing down the excavation operation."
Authorities have pursued multiple leads as to Hoffa's whereabouts since his disappearance in 1975. He was last seen outside an Oakland County restaurant where he was to meet with a New Jersey Teamsters boss and a Detroit Mafia captain.
The latest tip about Hoffa's remains came from reputed Mafia captain Tony Zerilli, who, through his lawyer, said Hoffa was buried beneath a concrete slab in a barn in Oakland Township, north of Detroit.
The barn is gone, but FBI agents on Monday starting poring over the field where it used to stand.
On Tuesday, authorities used a backhoe to dig and move dirt around in the section of land. Authorities also called in forensic anthropologists from Michigan State University and cadaver dogs from the Michigan State Police.
"Certainly, we're disappointed" in the results, Foley told reporters Wednesday.