A teenage girl has been sexually assaulted by two men who attacked her in an alleyway in Chichester.
The 17-year-old was walking between Westhampnett Road and Swanfield Drive in the early hours of Tuesday when she was confronted.
The girl has been seen by specially trained officers, whose colleagues have been investigating the crime scene.
Police said the crime was "serious and unusual". They want to hear from people who were in the area at about 0030 GMT.