A man was flown to Perth with broken bones and internal injuries after he fell from the bonnet of a moving car in West Pinjarra last night.
Police were called to a property on Curtis Lane, near Beacham Road, about 5.10pm.
Insp. Trevor Davis said the man had jumped onto the car when a woman he had been arguing with tried to drive away.
He said the man had been trying to stop the woman, who he is believed to have been in a relationship with, from leaving by getting onto the car but he fell off.
A St John Ambulance spokesman said the man suffered a broken arm, a broken jaw, internal injuries, cuts and grazes.
He was airlifted to Royal Perth Hospital by the RAC Rescue helicopter.
The man's injuries were not life-threatening and he is this morning in a stable condition in hospital.
Police are investigating the incident.