The FBI says it has found no sign of the remains of former Teamsters union leader Jimmy Hoffa and is ending a dig in suburban Detroit. The announcement was made today by Robert Foley, head of the FBI in Detroit, just a few hours after digging resumed. The dig began Monday. Authorities have pursued multiple leads on Hoffa's whereabouts since his disappearance in 1975. This latest tip about Hoffa's remains came from reputed Mafia captain Tony Zerilli, who, through his lawyer, said Hoffa was buried beneath a concrete slab in a barn in Oakland Township. The barn is gone, but FBI agents pored over the field where it used to stand. (More Jimmy Hoffa stories.)