UPDATE: Police have confirmed the victim is a 35-year-old woman.
A 49-year-old man is helping them with their inquiries.
Homicide Detectives attended several addresses in Scarborough today while investigating the death.
POLICE closed part of the Mitchell Freeway overnight after finding a woman’s body in a car.
A statement from WA Police said officers found the woman’s body in a car being driven on the Cedric Street off-ramp at 12.35am.
The driver of the vehicle is helping police with their inquiries.
Drivers have been asked to avoid the area and traffic diversions are in place while Homicide Squad detectives investigate.
Main Roads said earlier that the strip between Karrinyup Road and Hutton Street had been closed, however one lane has since been reopened.
— Main Roads WA (@Perth_Traffic) July 15, 2017