FOUR people remain in hospital following a crash in Upper Swan yesterday afternoon.
The multiple car crash at 4.05pm was the result of an initial collision between a red southbound Ford Falcon and a northbound Isuzu truck on Great Northern Highway near Apple Street.
The Ford Falcon lost control after the truck crash and collided with a Nissan Patrol and a Ford Ranger travelling in the opposite direction.
The front seat passenger of the Ford Falcon, a 28-year-old man, sustained life-threatening injuries and was airlifted to Royal Perth Hospital where he is in a critical condition.
Another passenger of the Ford Falcon, also a 28-year-old man, is in a serious but stable condition.
The 16-year-old male driver of the Nissan Patrol and his 56-year-old female passenger received serious injuries but are in a stable condition.
Major Crash investigators would like to speak with anyone who saw the crash or any of the vehicles prior to the crash.
Anyone with any information is asked to call Crime Stoppers on 1800 333 000.