Police have confirmed three young children were among the five people found dead at a Bedford home on Sunday.
The bodies were found at an address on Coode Street, Bedford after a man attended a regional Western Australian Police station on Sunday morning.
"The man now assisting police remains in custody, no charges have been laid at this time", police said in a statement.
Police early on Monday morning confirmed the children were twin two-year-old girls and a three-and-a-half-year-old girl.
The incident marks the third tragic event in recent months in Western Australia.
Assistant Commissioner Steel said police were trying to identify relatives to notify them.
Trump aide Papadopoulos gets 14 days in prison
Prosecutors sought a sentence of up to six months, while defence lawyers asked for probation. He had actually met them after joining Mr Trump's campaign.
Police at the scene of the incident in Bedford, Perth.
At the home, they discovered the deceased bodies of up to five people, including children.
He did not confirm the exact number of dead, nor did he detail what the relationship was between the man in custody and the deceased.
Locals said children were often seen playing in the front yard of the home.
"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".
"We are three hours into this investigation, I have no further detail in relation to those who are present at the location", he said.
Emergency declared as Tropical Storm Gordon heads for Gulf Coast
The National Weather Service in North Little Rock said rainfall would likely approach southeast Arkansas on Wednesday. A stray seagull fought the wind gusts and appeared to be floating in space over the volleyball nets.
"It's just so sad, they've got young kids - it's horrific on every level" neighbour Maria Manfredini told WA Today.
No charges have been laid yet and it is unclear whether the man is related to the victims.
"Depending on the size of that crime scene that will take a period of time, and it could be a number of days", Mr Steel said.
Seven people were shot and killed in the state in May.
"Up to five" bodies at the home in suburban Perth are believed to have been a mother, her children and their grandmother, news.com.au reported.
The age and gender of those found has not yet been revealed, although it is thought "there was at least one woman".
Spurs delay moving in to new stadium
The NFL game between the Oakland Raiders and Seattle Seahawks set for October 14 will also have to be played at the 90,000 capacity arena.
The deaths of Katrina Miles, her parents Cynda and Peter, and children Taye, Rylan, Arye and Kadyn, were described as Australia's worst mass shooting since the Port Arthur massacre.