Is key to Hoffa mystery in the soil of a Michigan home?

Nearly 40 years after his disappearance, former Teamsters boss Jimmy Hoffa, pictured circa 1955, remains among America's most famous missing persons. Authorities have been searching for the once powerful union boss since he vanished in 1975. The mystery continues, as authorities in Michigan, acting on a tip, failed to find any human remains after digging up a driveway in Michi gan on Friday, September 28. Hoffa slumps in a chair at the Teamsters union office. He was one of the most powerful union leaders in America until being forced out of the organized labor movement. He went to prison in 1967 for jury tampering and fraud before being pardoned four years later. Hoffa appears at the Teamsters union convention in 1957, the year he first became union president. Hoffa, center, stands with other officials at the Teamsters convention, where he made a successful bid for control of the union in 1957. Hoffa testifies at a Senate Rackets Committee hearing in 1958. Hoffa on the phone at an airport in 1959. An office for Teamsters union local chapters that Hoffa set up. Hoffa eats with union leader Joseph Curran, left, in 1959. Hoffa holds a Teamsters rally at Madison Square Garden in New York in 1960. Hoffa leads supporters at a Teamsters convention in 1959. The Teamsters boss appears on the cover of Life magazine on May 18, 1959. The headline reads, "A National Threat: Hoffa's Teamsters; Part 1: Sources of a Union's Uncurbed Power." Hoffa, pictured circa 1960, was a powerful labor leader at a time when unions wielded a great deal of sway over elections and were notoriously tied to organized crime. From left, "Meet the Press" moderator Ned Brooks, Lawrence K. Spivak and Hoffa appear at an NBC studio. Hoffa and his son, James Phillip, enter a federal courtroom in July 1964. His son is the current president of the Teamsters. Hoffa, second row, center, leaves court after being found guilty of jury tampering in 1964. Hoffa at the Pittsburgh airport in 1971 on his way back to federal prison after being let out to visit his ailing wife. He was released from prison later that year on the condition he not resume union activity before 1980. Hoffa poses for a picture on July 24, 1975, less than a week before his disappearance. He was 62 at the time. A Bloomfield Township, Michigan, police officer stands beside Hoffa's car after the former labor leader's disappearance in July 1975. Hoffa was last seen at a restaurant in suburban Detroit on July 30, 1975. Police sweep a field in Waterford Township, Michigan, in search of Hoffa's body in July 1975. Demolition workers in 2006 tear down a horse barn for the FBI in a search for Hoffa's remains in Milford, Michigan. The FBI had received a tip that Hoffa was buried on the farm. Police are set to take soil core samples at this Roseville, Michigan, house in the hunt for Hoffa. Police call a tip about a body being buried there around the same time as Hoffa's disappearance credible. The tipster did not claim it was Hoffa's body, authorities say. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Two soil samples are taken from a home A tipster says he saw a body buried there a day after Hoffa's disappearance Hoffa's disappearance 35 years ago captured public imagination Roseville, Michigan (CNN) -- Authorities were expected to announce Monday if soil samples taken from a Michigan home once owned by a bookmaker yielded evidence of the remains of former Teamsters boss Jimmy Hoffa. Two soil samples were taken from a home in the suburban Detroit community of Roseville last week after a tipster claimed he saw a body buried on the property a day after Hoffa disappeared in 1975. The samples were taken from beneath a storage shed and sent to a lab at Michigan State University after a search last week failed to turn up any "discernible remains," such as bones, body parts or other evidence, Roseville Police Chief James Berlin said. The search of the Roseville property is the latest in an on-again, off-again search for Hoffa, whose disappearance 35 years ago captured the public imagination. Police: Hoffa a wound that won't go away Hoffa, then 62, was last seen on July 30, 1975, outside the Detroit-area Machus Red Fox restaurant. He was there ostensibly to meet with reputed Detroit Mafia street enforcer Anthony Giacalone and Genovese crime family figure Anthony Provenzano, who was also a chief of a Teamsters local in New Jersey. Giacalone died in 1982; Provenzano died in 988 in prison. The tipster, a former gambler, once did business with a man tied to Giacalone, said Dan Moldea, author of "The Hoffa Wars." Moldea said he first spoke to the tipster in March and then sent him to police. Despite those links, Moldea said it seems unlikely that anyone would have been buried at the site, in full view of the neighborhood. And if a body had been buried there, little would remain, he said. The lab tests being conducted on the soil samples will be able to determine if human remains were buried at the site, but will not identify them, Berlin said. If human remains are discovered, investigators would have to return for a more complete excavation, he said. Even so, Berlin doubts any possible human remains discovered at the house would be those of Hoffa. I would like to bring closure to his family and the tens of thousands of Teamsters. Chief James Berlin, Roseville Police Department "It would be great if it was, because I would like to bring closure to his family and the tens of thousands of Teamsters that idolize this man, and just the southeast of Michigan," said Berlin, of the Roseville Police Department. "This is kind of like an open wound that won't go away. Every couple of years this happens, and all you guys come out here and we have to relive it." But Berlin said the "time line doesn't really add up." Hoffa was of the most powerful union leaders at a time when unions wielded enormous political sway. He was forced out of the organized labor movement when he went to federal prison in 1967 for jury tampering and fraud. President Richard Nixon pardoned him in 1971 on condition he not attempt to get back into the union movement before 1980. Hoffa believed Giacalone had set up the meeting to help settle a feud between Hoffa and Provenzano, but Hoffa was the only one who showed up for the meeting, according to the FBI. Giacalone and Provenzano later told the FBI that no meeting had been scheduled. The FBI said at the time that the disappearance could have been linked to Hoffa's efforts to regain power in the Teamsters and the mob's influence over the union's pension funds. Police and the FBI have searched for Hoffa intermittently. In September 2001, the FBI found DNA that linked Hoffa to a car that agents suspected was used in his disappearance. In 2004, authorities removed floorboards from a Detroit home to look for traces of blood, as former Teamsters official Frank Sheeran claimed in a biography that he had shot Hoffa. Sheeran died in 2003. Two years later, the FBI razed a horse barn in Michigan following what it called "a fairly credible lead." Urban lore long suggested that Hoffa was buried around the end zone at the former Giants Stadium in New Jersey. CNN's Chuck Johnston and Stephanie Gallman contributed to this report.