U.S. Central Command officials have put Defense Department contractors working in Afghanistan on notice about a sophisticated fraud scheme in which criminals pose as military contracting officials, according to documents. The developments were disclosed in a March 6 memo from the commanding general of CENTCOM's Joint Theater Support Contracting Command, Army Brig. Gen. Stephen Leisenring. The memo describes methods remarkable for their resemblance to legitimate military contracting practices, including false contract documents and authentic-looking email exchanges from made-up military officials...