Mandurah Detectives are seeking information to help with their investigation into a serious assault in Secret Harbour on February 24.
A 21-year-old man was with friends at a bar on Oasis Drive, Secret Harbour, when he went outside sometime between 11-11.25pm.
He was standing on the pathway at the front of the bar when he became involved in a fight.
During the altercation the victim was punched and he fell backwards, hitting his head on the pavement.
He received serious head injuries as was rushed by ambulance to Royal Perth Hospital.
Police believe several people were nearby and detectives would like to speak to anyone who saw the incident.
Anyone with any information is asked to call Crime Stoppers on 1800 333 000, or report the information online at crimestopperswa.com.au.