Up to five corpses, including children, have been found dead in a home in Perth.
A man in his 20s came to the police on Sunday before officers visited a house on Coode Street in Bedford, where the bodies were found.
"It's kind of tragic when incidents like this happen, it sends a shockwave to the Western Australian community," Assistant Commissioner of the Metropolitan Region Paul Steel told reporters on Sunday.
The man is in custody and is interviewed by the police.
The police say there are no constant concerns for the safety of the community.