DETROIT -- When authorities dig into a Roseville, Mich., driveway Friday in search of potential human remains -- possibly those of missing Teamsters boss Jimmy Hoffa, a tipster claims - they'll take a tube full of soil and have it examined by a forensic anthropologist.

Police are skeptical an anomaly spotted underneath the driveway with ground-penetrating radar will turn out to be the remains of Hoffa, who vanished from a restaurant parking lot in Oakland County in 1975 and who a tipster says is under the driveway.

"The timeline doesn't add up, but we do believe there may be something down there," Roseville Police Chief James Berlin said.

To find out what's under the driveway of the home in the 18700 block of Florida, Berlin said authorities from the state's Department of Environmental Quality will take a soil sample. He said a drill will be used to bore a cylinder _ roughly 4 inches wide and 6 feet long _ into the ground after a small portion of concrete is removed from the driveway.

He said the city of Roseville is not being charged for the soil sample retrieval, adding this is being treated as mutual aid.

"They've been fantastic," Berlin said of the Department of Environmental Quality. "Our goal is to minimize the damage to their property as much as possible."

Once the tube of earth is brought up, it will be capped at both ends and hand-delivered to a forensic anthropologist at Michigan State University, Berlin said. He hopes to have the results next week.

If the anthropologist discovers traces of human remains, he said, the driveway will be excavated.

The homeowner declined to be interviewed Wednesday.

Hoffa, 62, disappeared on July 30, 1975, from the parking lot of the then Machus Red Fox restaurant in Bloomfield Township. He had gone there for a reconciliation meeting with Anthony "Tony Pro" Provenzano, a mob-connected New Jersey Teamster official, and Anthony "Tony Jack" Giacalone, a Detroit mafia captain.

The FBI theorized the men had Hoffa, who ran the union from 1957-71, killed to prevent him from regaining the Teamsters presidency and ending the mob's influence over the union and access to pension funds.

Hoffa's body has never been found, and no one has been charged in his disappearance, despite thousands of tips over the years.

After interviewing the latest tipster, who police have not identified, Berlin said he contacted the Michigan State Police, which recommended calling in the state's Department of Environmental Quality to scan the driveway with the radar.

The tipster told police he believes Hoffa is under the driveway. The tipster told the Detroit Free Press the man who once lived in the Roseville house was a bookie for Giacalone.

Police said ground-penetrating radar revealed an anomaly about 2 feet underground. Berlin cautioned the anomaly could be a dead dog or a tree root.

"We are not making the assumption it's Jimmy Hoffa," he has said. "We do not believe it's Jimmy Hoffa."

This week's search is the latest of many. In 2006, the FBI spent 14 days digging at a horse farm in Milford, Mich., in an unsuccessful effort to find Hoffa's remains.