Police have arrested a man for allegedly impersonating an officer and sexually assaulting a teenager in Bed-Stuy. 

According to investigators, 47-year-old Walter Barnes, of Brooklyn, offered the 18-year-old victim a ride on Oct. 2, claiming to be a cop. They say he talked into a radio using police jargon and referenced officers who drove by in a marked car. 

Authorities say Barnes told the teen that she would be arrested if she did not perform a sexual act on him after picking her up near Broadway and Gates Avenue. He then drove her to the vicinity of Aberdeen Street and Bushwick Avenue. 

At a third location near Sherlock and Herkimer streets, the girl was able to fight off Barnes and run for help. 

Barnes is facing several charges, including rape, aggravated sex abuse and criminal impersonation of a police officer.