It took Australian police more than three hours to check on two young children after their worried Kiwi mother raised the alarm, but by then their father had already murdered them, an inquest in Perth has heard.
Officers found the bodies of Zaraiyah-Lily Headland, 5, and Andreas Headland, 3, on a bed inside a Yanchep home on October 20, 2016.
Their father Jason Craig Headland - who was also found at the home with self-inflicted injuries - pleaded guilty to their murders and was sentenced to life in prison, with a minimum of 31 years to be served.
The children's cause of death could not be ascertained but they had been drugged and asphyxiated.
The actions of police immediately before the deaths are now being investigated in the West Australian Coroners Court.
Counsel assisting the coroner Toby Bishop, said the children's mother, Anatoria Takiwa, formerly of Paraparaumu, had gone to Joondalup police station to request a welfare check after she received a disturbing phone call from her estranged partner.
"By the time police officers arrived at the family home a few hours later, the children were already deceased," he said in his opening address on Tuesday. Ms Takiwa's friend Katie Cheeseman was with her when she received that fateful call from Headland.
"I'm going to hurt you ... I'm going to break your heart into 50 million pieces. Say goodbye to your kids. This is the last time you're going to speak to them," Headland said.
Ms Cheeseman said she considered Headland might kidnap the children but deep down thought he was going to harm them.
"I just knew we needed help," she testified.
Ms Cheeseman said she thought it would be unsafe for them to go to the house, so they went to the police at 6.49pm and spoke to a recruit, who then informed her superiors.
"I thought they needed to go and make sure the kids were OK," Ms Cheeseman said. "I thought that they would do it straight away.
"I expected them to do what they're meant to do in those situations." After they had been at the station for about half an hour, the recruit spoke to Headland on the phone and he said he would bring the children there, the inquest heard.
But Ms Cheeseman said she and Ms Takiwa understood the children were with their grandparents, otherwise they would not have left the station. When Headland failed to arrive at the station, the recruit unsuccessfully tried to call him, then called Ms Takiwa and was told Headland might be at the marital home in Yanchep, Mr Bishop said.
The recruit created a job in the police system and gave it a priority three, which meant police were required to respond within one hour. Officers visited the home about 10.17pm, which was just under one hour, but three and a half hours since Ms Takiwa went to police with her concerns, Mr Bishop said.
Coroner Sarah Linton will consider the reasonableness of relying on Headland saying he would bring the children to the station.
She will also examine the appropriate time police should have been dispatched to check on the children.
The inquest continues.