Police discovered the decomposed body on Murdoch Drive yesterday.
A woman may have been living with her partner's decomposing body for several weeks before police were notified.
Their Murdoch Drive home was declared a crime scene after Police made the discovery yesterday morning.
A man in his 50s was found dead, but due to the recent hot weather authorities said it was difficult to know how long he had been dead.
The woman living in the Greenfields home did not report the death but is not being treated as a suspect in relation to the man's death.
Items were removed from the Mandurah home, an autopsy will be done to determine how the man died and a report for the Coroner will be prepared.
More to come.
Police seek witnesses to serious crash in Pinjarra
Local artist Emma Blyth inspires community to raise $10k for Mandurah kids facing hunger
Hunt continues for Baldivis ATM thieves
Channel 7 Mandurah Crab Fest a cracking success
Giant puppets, illuminated installations to descend on Baldivis Sports Complex
Man fined nearly $2k for undersize crab haul near Coodanup
Australia Post reveals Mandurah residents receive highest volumes of parcels
Safety Bay man charged over South West pursuit
Arson Squad continue investigation into Waikiki house fire