Police say the victim is a 17-year-old girl.
Investigators say the victim accepted a ride from a man who then pulled out a gun, drove her to the alley and sexually assaulted her. The girl was then able to get out of the car and call police. Crime scene video shows the victim's clothes in the alley.
The victim said her attacker's car was white. No description of the attacker was available.
The victim was taken to St. Mary's Hospital where she was treated and released.