Emergency companies attended a house on Monterey St in Nollamara at about 10.30pm (AWST).
They discovered a 26-year-old lady who had been injured.
An ambulance took her to Royal Perth Hospital, the place she later died.
Throughout a search of the realm, a police canine discovered a person hiding on the entrance of a neighbouring property.
The 40-year-old man, who police stated was recognized to the sufferer, is in police custody and helping with the investigation.