UNITED NATIONS – The deal looked simple enough: U.S. military equipment suppliers bribed an African defense minister's salesmen to secure part of a $15 million gig to outfit a presidential guard. But the salesmen were actually FBI agents. And the operation resulted in what U.S. authorities in January called their biggest foreign bribery sting to date, netting 16 indictments and 22 arrests of small arms and military equipment makers. At the center of the U.S. case is Richard Bistrong, a former Florida executive who first surfaced in a series of cases of bribes and bid-rigging for multimillion-dollar U.N. peacekeeping contracts....