A rookie police officer with the U.S. Navy Yard was killed in a one-car accident, apparently falling asleep at the wheel after working double shifts for at least three days.

Travis Harris, 27, died early Sunday morning in Fairfax County when his 2003 Ford Explorer veered off the road near the intersection of Sherwood Hall and Evening lanes in Mount Vernon and struck a tree. He had graduated from the police academy in March and was working as an officer at the Navy Yard.