Detectives have charged a fourth person over an aggravated burglary at an apartment in Halls Head.
It is alleged the 35-year-old man was one of several people who entered the property on Apollo Place on August 8, and once inside they assaulted the two occupants before stealing various items.
A 23-year-old woman received minor injuries and a 24-year-old man was taken to Peel Health Campus with a cut to his head and an arm injury.
The Madora Bay man has been charged with aggravated burglary and commit, aggravated armed robbery, possessing a prohibited drug and possessing drug paraphernalia.
He is next due to appear in the Perth Magistrates Court on September 9.
A 20-year-old woman and a 36-year-old man both from Coodanup and a 31-year-old man from Greenfields were charged over the incident last week.
Lark Hill Sportsplex to undergo $3 million floodlighting upgrades
Arson Squad investigate Bunbury house fire
Construction begins on new Mandurah Hospital
Rockingham Flames men advance to NBL1 West grand final
Motorcycle passenger in critical condition after rider allegedly runs red light in East Rockingham
Two men charged over Australind murder
Last call for donations to support Mandurah's homeless
State Government commits to building $5 million electrical training facility at Rockingham TAFE
McDonald's approved for Dawesville