Midland Detectives have charged a Mandurah teenager with aggravated armed robbery after an incident in Beechboro.
It will be alleged the 15-year-old girl was one of three juveniles who assaulted a woman on Sunday, March 17.
About 10:15pm, an 18-year-old woman was walking to her vehicle, which was parked in the car park of a fast food restaurant on Altone Road, Beechboro.
It will be alleged after entering her vehicle another female entered the rear of the vehicle and demanded the victim exit the vehicle.
It is further alleged two more females approached and forced the victim to exit the vehicle before the group assaulted her.
The victim was taken to Royal Perth Hospital for treatment.
A 15-year-old girl from Lockridge and a 16-year-old girl from Perth, have also been charged with aggravated armed robbery.
They are due to appear before the Perth Children's Court today.