Police will allege Mara Quinn, 41, was killed not long after returning from work to her home in Bedford.
They say she returned home to her family about 11pm on September 3 after finishing a shift as a Coles shelf-stacker in the inner-city suburb of Inglewood.
That’s when police allege she was murdered by her partner Anthony Robert Harvey, 24.
He is also accused of killing their three children, three-year-old Charlotte and two-year-old twins Alice and Beatrix, late at night at the Coode Street house.
The following day, police allege he killed Mara’s mother Beverley Quinn, 73, before staying in the house for several days.
The bodies weren’t discovered by police until Sunday, after Mr Harvey presented to a police station in Pannawonica, approximately 1400km north of Perth.
Police have now left the crime scene, but the floral tributes at the site of an unthinkable tragedy have continued to grow.