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.
Concerns for missing Bertram woman
Concept designs released of Safety Bay Foreshore development
McLaren driver clocked speeding at 259km/h on Forrest Highway
Man found dead inside Orelia home, one in custody
Nominations now open for Mandurah's 2027 Community Citizen of the Year Awards
Romanian national charged after police uncover ATM card skimming across Rockingham, Mandurah
Cooloongup man sentenced for poisoning dog before dumping body in rubbish bin
Bird flu vaccinations begin on little penguins at Penguin Island
Man fined $10k over shocking cruelty towards German Shepherd in Baldivis