Sources : Five Blackwater guards charged in 2007 fire that killed 17 people . Sixth suspect in plea negotiations , whereabouts unknown . Charges are not publicly known because indictment is under way . A sixth security guard is in plea negotiations , the sources told CNN . Charges could be made public as early as Monday .
Sources : Five Blackwater guards charged in 2007 fire that killed 17 people . Sixth suspect in plea negotiations , whereabouts unknown . Charges are not publicly known because indictment is under way . Charges could be made public as early as Monday .