The Stranger (1995)

The small town of Lakeview, Arizona has been taken over by a violent gang of bikers. The local sheriff is too afraid to do anything to stop them ever since his fiancee was murdered while trying to bring evidence against the gang to the FBI. One day, a mysterious woman, who looks exactly like the sheriff's fiancee, comes riding into town on a motorbike and starts killing members of the gang. Who is this avenging mystery woman?