A Marine honor guard carries the casket of Marine Sgt. Sean Callahan of Warrenton, Va., , who was killed in Afghanistan, during a burial service at Arlington National Cemetery in Arlington, Va., ... more 
A Marine honor guard carries the casket of Marine Sgt. Sean Callahan of Warrenton, Va., , who was killed in Afghanistan, during a burial service at Arlington National Cemetery in Arlington, Va., Monday, May 2, 2011. less 
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Associated Press | Photo By Evan Vucci
Mon, May 2, 2011 1:57 PM EDT