By Joseph Lichterman
OAKLAND TOWNSHIP, Michigan (Reuters) - The latest search for the remains of former Teamsters boss Jimmy Hoffa ended on Wednesday in a field near Detroit, where federal agents had dug with heavy equipment and shovels for three days in the hope of answering the decades old question, "Whatever happened to Jimmy Hoffa?"
Since Monday, 40 agents for the Federal Bureau of Investigation, the Michigan state police and Oakland County sheriff's office, and forensic anthropologists from Michigan State University had combed an acre of the overgrown field not far from where Hoffa was last seen alive in 1975.
"We did not uncover any evidence relevant to the investigation on James Hoffa," Robert Foley, head of the FBI's Detroit office, told reporters. "Of course we're disappointed."
The search for Hoffa, who was 62 when he disappeared and is thought to have been killed by members of organized crime, has become near mythical, providing fodder for rumors, books, and movies, including 1992's "Hoffa," starring Jack Nicholson.
Law enforcement officials decided to search the field after reputed mobster Anthony Zerilli, 85, told the FBI Hoffa was buried there. When Hoffa disappeared, the property was owned by a man Zerilli said was his first cousin. Zerilli is the son of former reputed Detroit mob boss Joseph Zerilli.
Foley said the search for Hoffa has been worthwhile, but he did not provide details about how much it has cost.
"The FBI and its partners, we're not a corporation. We do not have a profit margin as a bottom line," Foley said. "What we have instead as a bottom line is the search for justice."
A man who showed up at the dig site on Tuesday carrying a shovel and wearing a horse head mask, which harkened to the 1972 movie "The Godfather," criticized the FBI for continuing to pursue the case.
"What does finding the body prove even if he was here?" said the man, who identified himself only as "Mr. Ed", a reference to a fictional talking horse in a 1960s American television series.
The search began on Monday at a concrete slab in the field, about 20 miles from a restaurant where Hoffa was last seen alive.
Hoffa, father of current Teamsters President James Hoffa, led the union from 1957 to 1971. In his final years as union president, Jimmy Hoffa was imprisoned for fraud and jury tampering. He was released in 1971 after President Richard Nixon commuted his sentence.
Law enforcement authorities have long thought that members of organized crime ordered Hoffa's killing to prevent him from regaining control of the Teamsters.
Zerilli's attorney, David Chasnick, said he had not spoken with his client since the FBI called off the search on Wednesday.
There have been other searches for Hoffa in the Detroit area. In September 2012, police took a soil sample from behind a private home in Roseville, Michigan, after receiving a tip.
Suggestions about where Hoffa may be buried have included under an end zone in Giants Stadium in East Rutherford, New Jersey.
"I would say that we're always hopeful that we'll get a lead that will lead us to a position in which we can conclude this investigation in full for the process of justice and also for the family," Foley said.
(Additional reporting by Nick Carey in Chicago, Bernie Woodall in Detroit and Ellen Wulfhorst in New York; Writing by Bernie Woodall; Editing by Toni Reinhold)