Five bodies, including those of twin two-year-old girls, another girl, aged three-and-a-half, and their mother and grandmother, have been found at a home in Bedford in north-east Perth on Sunday.
Police said a man in his 20s reported an incident at the Coode Street residence when he attended a police station in country Western Australia. He remains in custody.
The ages of the children and their relationship to the two adult women found at the Bedford address were confirmed on Monday by WA Police.
Homicide detectives and specialist forensic police will on Monday continue to comb the home for evidence and clues to what happened after the shocking discovery.
Assistant Commissioner Metropolitan Region Paul Steel said homicide detectives started a forensic examination shortly after noon on Sunday and could take days to complete.
“It is a tragic thing when incidents like this occur,” he said.
“It is tragic not only for the family and the friends, it is also tragic for those first responders who are forced to attend such scenes.
“It does send a ripple through the community of Western Australia.”
It’s believed the man was known to the victims with media, citing neighbours, saying a couple with three little girls, one aged three and 18-month-old twins, lived at the home.
Specialist forensic police are expected to continue a meticulous examination of the crime scene on Monday.
Assistant commissioner Steel said officers were still working to determine the timeline of what happened.
The Western Australia Police Force later issued a statement on Facebook: “The man is currently in custody and assisting police with their inquiries. There are no ongoing concerns for public safety as a result of this incident.
“The WA Police Force will continue to apply our efforts to this matter as a priority, and the Homicide Squad will ensure a professional and meticulous investigation is undertaken.”
The tragedy comes just weeks after several members of a family were slain at Ellenbrook.
A 19-year-old man was charged with the murders of an eight-year-old boy, a 15-year-old girl and their 48-year-old mother at a house in the Perth suburb.