FBI Search Ends, Hoffa Mystery Remains

Dozens of FBI agents, anthropologists and archaeologists are gone, and the latest massive search for Jimmy Hoffa's remains has come up as empty as the giant crater investigators have left behind.

The horse barn at Hidden Dreams Farm in the Detroit suburb of Milford Township, Mich., that agents tore down now takes its place alongside the end zone in Giants Stadium in East Rutherford, N.J., a landfill on Staten Island, and the many other places where Hoffa's remains were not found.

"After a thorough and comprehensive search, no remains of Mr. Hoffa have been located," said Judy Chilen, assistant special agent in charge of the FBI's Detroit office.

Those who have long suspected mob involvement are not surprised that Hoffa's whereabouts remain a mystery.

"It just makes logical sense with a high-profile guy like this they would just want to totally destroy and eliminate the body," said Vince Wade, a Hoffa case expert. "They don't want any evidence hanging around."

Some theories say Hoffa's remains were boiled in a tank of animal fat -- or churned into the pavement on the New Jersey Turnpike. The FBI's latest 13-day-long dig is now fodder for late-night comics.

Late-Night Comic Fodder -- but No Laughing Matter

"Officials say it's the first time they've ever been to Detroit and not found a body," said Conan O'Brien on "Late Night With Conan O'Brien."

"They have a lead on the whereabouts of Jimmy Hoffa. They said he was last seen on a duck-hunting trip with Dick Cheney," said David Letterman on "The Late Show."

At least one Congress member -- Rep. Joe Knollenberg, R. Mich., -- wasn't laughing.

"I think it's a case where the taxpayer has an interest too," he said. "We hear it's hundreds of thousands of dollars."

The FBI now estimates the cost of the latest Hoffa search was $250,000. More money will be spent to rebuild the barn. Why is finding Hoffa worth all of this taxpayer money?

"For the past 31 years the Mafia's trophy is its ability to get away with the murder of Jimmy Hoffa," said Dan Moldea, author of "The Hoffa Wars." "The FBI needs to solve this case in the war against organized crime."

But, after years in the trenches, federal agents are still coming up empty.

ABC News' Barbara Pinto reported this story for "Good Morning America."