A woman's body has been found in a bushland grave in Perth's southeast and a 31-year-old man who was known to her is being questioned about her suspicious death.
Police searched bushland in Ashendon on Thursday and believe the woman they discovered on Thursday is Julie Anne Cooper, 55, of Doubleview, who last spoke to family on August 17 when she advised she would be out of contact for two weeks.
"We've been investigating it for a while - the exact date I will not release," homicide squad detective senior sergeant Manus Walsh told reporters.
Police are searching for her silver 2006 Toyota Camry sedan, which had registration plates 1CGT 526 but different plates may now be fitted to the vehicle.
"We believe that those plates have been changed," Det Snr Sgt Walsh said.
"Her car, we believe, was in the possession of someone else who has been possibly involved in what may have been a lawful transaction.
"There's been an exchange that has led to that vehicle going to someone else."
That person might not know they have Ms Cooper's vehicle, the detective said.
Asked if her bank account and phone had been used, he said some of her personal items had been accessed.
Ms Cooper's family has been notified.
Police are urging anyone with information about the whereabouts of the vehicle to get in touch.