Police are looking for three men who threatened a woman with a knife and stole her purse at a Rogers Park bus station Saturday.

The 20-year-old victim was waiting for the bus between Sheridan Road and W. Touhy Avenue at 10:15 p.m., when the muggers approached, police said.

The robbers took her bag containing $500, her driver's license and some books and then fled on foot from the scene.

The victim, who was not injured, called police immediately.

Officers are still investigating.