A man has received serious head injuries after a brawl in Cooloongup.
Police were called to a shopping complex near Mataitai Loop around 2am on Sunday after reports of a fight between a group of people.
A man in his 20s received serious but non-life threatening head injuries and was taken to Royal Perth Hospital.
It is believed the group are known to each other.
Detectives are investigating the circumstances surrounding the assault and would like to speak with anyone who may have seen the incident.
Anyone with information is asked to contact Crime Stoppers on 1800 333 000 or report online at crimestopperswa.com.au.