Police have charged Shawn Adam Newton with the murder of Perth mum of three Rebecca Jane Gascoigne.

Police captured Mr Newton on Monday after more than a week on the run.

Mr Newton had been wanted in relation to the death of the 35-year-old mother-of-three, whose body was found in a car on the Mitchell Freeway on July 15.

The 42-year-old was arrested shortly after 2pm on Monday at a business near Whitfords Shopping Centre on Marmion Avenue.

Officers were called to the area by a member of the public and he was arrested without incident.

On Tuesday, Homicide Squad Detectives announced they had charged a 42-year-old Lockridge man with murder, deprivation of liberty and threats with intent to compel the doing of an act.

He will appear before the Perth Magistrates Court on Wednesday and police say further charges are pending. 

The search for Mr Newton began on July 15 after police found Ms Gascoigne's body in a Mitsubishi Lancer being driven on the Cedric Street on-ramp at around 12.35am.

At the time police said the driver of the Mitsubishi Lancer, a 49-year-old man, had been helping police with their inquiries - but that Mr Newton was wanted for questioning over the grisly discovery.

Detective Senior Sergeant Bailey said the 49-year-old, Mr Newton and Ms Gascoigne were all known to each other.

Police previously searched two houses in Scarborough in connection with the investigation. One of the homes was on Abbett Street, the other on Wilton Place.

Police returned to the Abbett Street home on July 18 and also searched nearby bushland in Karrinyup.