1984 Midwest pipe bombings  The 1984 Midwest pipe bombing was a plot involving a series of pipe-bombs planted in Minnesota, Illinois and Wisconsin, by Earl Steven Karr. In May and June 1984, an American, Earl Steven Karr, planted over 20 pipe-bombs about Minnesota, Illinois and Wisconsin. He was arrested in Mason City, Iowa after a pipe-bomb he was transporting detonated in the trunk of his car. Only one person is known to have been injured by his explosives. Notes left near the bombs took credit in the name of the "North Central Gay Strike Force Against Public and Police Oppression."