TWO elderly people were seriously injured after a four-vehicle crash on the Kwinana Freeway, Bertram yesterday.
Major Crash officers are investigating how four vehicles collided while they were all travelling south at 5pm.
The vehicles involved were a blue coloured Mazda CX5, a black coloured Ford Falcon sedan, a blue coloured Nissan Navara and a Freightliner truck.
The circumstances surrounding the crash and sequence of the vehicles colliding is under investigation.
A 78-year-old woman, who was a passenger in the Mazda, suffered life-threatening injuries and is in a critical condition in Royal Perth Hospital.
The driver of the Mazda, a 77-year-old man, received serious injuries and is in a critical but stable condition in Fiona Stanley Hospital.
The occupants of the other three vehicles were treated for minor injuries.
Major Crash investigators would like to speak to anyone who may have seen the crash, or has dash camera footage of the crash or saw any of the vehicles prior to the crash.
Anyone with any information is asked to call Crime Stoppers on 1800 333 000 or make a report online .