Prince William County Police are asking for the public's help in finding a man who sexually assaulted a 14-year-old girl.
Police released a computer-animated sketch of the suspect Saturday.
Investigators say the man approached the teen outside the Potomac Library in Woodbridge Friday afternoon.
The accuser said the man came up behind her, sexually assaulted her, then took off.
The suspect is described as a white male in his late teens or early 20's. He's tall with a thin build and has a beard.
Police are offering up to $1,000 to anyone with information on this man.