Agents used a backhoe Saturday to dig at the site of a barn that had been demolished a few days earlier as the FBI resumed its search for the remains of labor leader Jimmy Hoffa.

It was the 11th day of searching at the Hidden Dreams Farm about 30 miles (48 kilometers) northwest of Detroit.

Digging at the 89-acre (36-hectare) site would continue through the Memorial Day holiday weekend, said FBI spokeswoman Dawn Clenney. She said nothing significant was found Friday.

Agents have said they have a credible tip that the former Teamsters boss is buried at the farm, which at one time was owned by Hoffa associate Rolland McMaster.

A government investigator has said that Donovan Wells, who lived on the land at the time, was the one who gave the FBI the tip that has sparked the intense effort.

Wells' lawyer, Joseph J. Fabrizio, has said his client told the FBI in 1976 that he saw suspicious activity on the farm around the time of Hoffa's disappearance.

Hoffa last was seen on a night he was scheduled to have dinner at a restaurant in Bloomfield Township, about 20 miles (32 kilometers) from the farm. He was supposed to meet with a New Jersey Teamsters boss and a Detroit Mafia captain, who both are now dead. His disappearance is one of America's great current-day mysteries.