A 23-year-old man is in a serious but stable condition in hospital this morning after he was shot in the chest at Cooloongup overnight.
Police were advised a man was being treated for a gunshot wound at Rockingham Hospital about 8.30pm.
The man was later taken to Royal Perth Hospital.
Police are today investigating the circumstances surrounding the shooting.
About 7.30pm, police received reports of people fighting on Annean Loop, brandishing shovels and baseball bats.
Subsequent callers said two cars were driving recklessly and up to 20 people were involved in a brawl.
One caller told police they had heard shots fired.
Insp. Trevor Davis said detectives had spoken to several people at the scene, but they were still investigating.
He urged anyone with information on the shooting to contact Crime Stoppers on 1800 333 000.