Once again, the search comes up empty. Tests on soil samples in a backyard in Michigan where former Teamsters boss Jimmy Hoffa was thought to be buried came back negative Tuesday. The tests showed no traces of Hoffa—or anybody else—buried at the tipped-off site. The suburban Detroit home was the latest false lead, with past suspected burial sites including a horse farm and even the underbelly of a swimming pool. The former union leader was last seen in 1975 on the day he was supposed to meet with a New Jersey Teamsters boss and a Detroit mafia captain.