Prince William County police are asking for the public's help finding a man who sexually assaulted a 14-year-old girl.
Police released a computer-animated sketch of the man Saturday.
Investigators say he approached the teen outside the Potomac Library in Woodbridge Friday evening.
The accuser said the man came up behind her, spoke to her, sexually assaulted her and then took off when the victim received a phone call.
The library was closed at the time.
The man is described as a white male in his late teens or early 20s. He's about 6-feet-2-inches to 6-feet-5-inches tall with a thin build, pale skin, thin mouth, pointy nose and a messy beard. He was wearing a gray or white jacket over a turtleneck, baggy jeans, white shoes, a gray knit hat and glasses with small, rectangular frames. He had a northern accent -- possible from New Jersey.
Police are offering up to $1,000 to anyone with information on this man.