Chilling details have been revealed in court of the deaths of three generations of the one family who were dead inside a suburban Perth for a week.
Their accused killer, the children's father Anthony Harvey, faced court this afternoon charged with five counts of murder after police discovered the bodies of twin two-year-old girls, their three-year-old sister, mother and grandmother yesterday.
Mr Harvey appeared on video link from Karratha Magistrates Court wearing a t-shirt, jeans and no shoes.
The court was told the murders of the children children Charlotte, Alice and Beatrix Harvey and their mother Mara Quinn took place on September 3, and their grandmother Beverley Quinn the next day on September 4.
When magistrate Joe Randazzo asked Mr Harvey if he understood each murder charge he simply said "I understand".
The 24-year-old stared at the ground and showed no emotion while on video.
He is due to appear again via video link on September 19.
WA police commissioner Chris Dawson told media this afternoon police will allege no gun was used but "several weapons".
"What we are alleging is a blunt instrument and knives were used," he said.
Commissioner Dawson said the two adults were allegedly killed in the kitchen and the children allegedly in other rooms of the house.
He said they were alleging Mrs Quinn was murdered the following morning when she arrived at the family home.
Commissioner Dawson said they would allege Mr Harvey stayed at the home for a "number of days" before he turned himself into police.
He said in the last four months 15 people had died in three separate family tragedies in the state.
"Crime's like this have a devastating impact on family, friends and indeed the wider community," he said.
"No matter that most of us did not immediately know this family, there is a sense of shock and indeed even at times anger for what has taken place."
He said he could understand why West Australia felt affected by the latest "atrocity" and urged anyone who was experiencing any kind of anxiety to contact helplines.
Harvey surrendered himself to Karratha police station yesterday afternoon, a town more than 15 hours north of the Perth suburb of Bedford where the family was found.
A number of neighbours confirmed to news.com.au Ms Quinn was employed as a fly-in-fly-out (FIFO) worker for a West Australian mining company.
Karratha, in the state's mining region of Pilbara, is a busy, temporary base for workers employed in the sector.
It's believed Harvey gave Karratha police officers information about the family, which led officers in Perth to attend the Coode St home.
Police declined to explain what Harvey said to lead them to the scene.
WA Police told news.com.au he spent the night being interviewed by detectives and was helping them with their inquiries.
According to WA Today, Mara Quinn, 47, lived in the Bedford home with Harvey. The grandmother was 74.
In August 2014, Ms Quinn took to social media to announce she was newly engaged.
Her first daughter was born about six months later.
The street and house were still cordoned off this morning with police forensic teams saying it would take them at least three days to investigate the scene.
The house is located on a busy road near a number of schools.
Early this morning, as kids hopped off their buses across the road from the home, they were herded away from the scene by police.
The house is less than 500m away from John Forrest Secondary College, Chisolm Catholic College and Hillcrest Primary School.