Milford Township, Mich. ? After tearing apart a barn, FBI agents began digging up the ground where it stood Thursday, taking photos and video and sifting through dirt by hand as they searched for Jimmy Hoffa’s remains at a suburban Detroit farm.

After a backhoe dug a hole at the site, FBI agents and crime-scene investigators jumped in to take pictures and comb through the soil. At one point, two dogs were sent into the hole. But after seven hours of digging, FBI spokeswoman Dawn Clenney said nothing significant was found. She said the search was expected to continue through the Memorial Day weekend.

The 100-by-30-foot barn was torn down Wednesday as the FBI scoured Hidden Dreams Farm, which once was owned by a Hoffa associate and is not far from where the former Teamsters chief vanished in 1975.