FBI Special Agent Bob Foley, head of the agency's Detroit office, told CNN at the scene that the information leading to the search "reached the threshold of probable cause, which was sufficient to allow us to obtain a search warrant." The paperwork supporting the search warrant is under seal.
"If it didn't rise to that level then, certainly, we wouldn't be out here," Foley said.
Hoffa's disappearance and presumed death have vexed investigators. As recently as October, soil samples were taken from a home in a suburban Detroit community after a tipster claimed he saw a body buried in the yard a day after Hoffa disappeared.
The soil samples were tested, and showed no evidence of human remains or decomposition.
Zerilli was freed in 2008 after his last prison sentence. Keith Corbett, a former U.S. attorney, told CNN earlier this year that Zerilli headed a Detroit organized crime family from 1970 to 1975, but was in prison when Hoffa vanished.
In an interview with CNN affiliate WDIV-TV, Zerilli denied playing any role in Hoffa's disappearance.
Zerilli told CNN affiliate WXYZ on Tuesday that he hoped authorities would find the remains of his "good friend," to put Hoffa's family at ease and put this story to rest.
"I'd like to see him exhumed and be buried properly, like he deserves to be," he said.