Five Blackwater Worldwide security guards have been indicted and a sixth was negotiating a plea with prosecutors for a 2007 shooting that left 17 Iraqis dead and became an anti-American rallying cry for insurgents, people close to the case said Friday. Prosecutors obtained the indictment late Thursday and had it put under seal until it is made public, perhaps as early as Monday. All who discussed the case did so on condition of anonymity because the matters remain sealed. Six guards have been under investigation since a convoy of heavily armed Blackwater contractors opened fire in a crowded Baghdad intersection on Sept. 16, 2007. Witnesses said the shooting was unprovoked but Blackwater, hired by the State Department to guard US diplomats, says its guards were ambushed by insurgents while responding to a car bombing.