A female victim reported that at around 1230 hours she was at the ticket machines when a suspect grabbed her Iphone 5 (estimated value $200, unknown serial number at this time) from behind and whispered to the her that he had a knife. The suspect fled on foot with the victim’s Iphone towards Muni. (Suspect description: Black male, 19-23 years old, short hair, wearing a white sweater and baggy blue jeans.) The victim was not injured. The investigating officer will be requesting station video.