The 33-year-old told officers he was standing near a walking trail in the 4300 block of Dale Boulevard of Woodbridge around 7:30 p.m. when someone pressed something against the back of his head, the Prince William County police said. The man didn't say if it felt like a gun, but he didn't turn around to find out.
The suspect demanded cash and ran away once he'd robbed the man. He sprinted toward the Minnieville Road area, police said, but a search helicopter and a K-9 unit couldn't find him.
He was wearing a dark-colored long-sleeve shirt and dark blue jeans, police said.
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