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.