Daughter who lost her Kiwi mum in brutal Perth killing says she tried to get help but system failed them - 'now we all suffer'

The daughter who lost her Kiwi mother and two siblings in a brutal triple murder in Perth, says her mum had been scared of the man charged over their deaths and had tried to get him help many times.

Today, Teancum Vernon Petersen-Crofts, 19, was charged with the murders of an eight-year-old boy, a 15-year-old girl and their mother, 48, at a house in the Perth suburb of Ellenbrook.

The daughter of the slain 48-year-old Kiwi woman is now blaming the Aussie health system for their deaths.

"My mum and my brother and sister they copped it. They had to suffer because the system failed them and now we all suffer," the woman who doesn't wish to be named told 1 NEWS.

She says her mother pleaded for help for the man allegedly behind the murders within the health system.

"My mum was going to the hospital and doctor saying what can I do? Who can help me?

"They were all saying he's sick but no one can help."

1 NEWS has been told Teancum Vernon Petersen-Crofts  is related to the victims and this morning, appeared to have a mental breakdown in court as he was charged with three counts of murder.

He looked around the public gallery before sitting down and accusing another person of carrying out the attack.

"A criminal wanted to take me out bush - he did it and he came back for my family," Petersen-Crofts said.

The magistrate told him he didn't need to say anything, but he replied: "I have to 'cos mamma is with me".

After the magistrate said Petersen-Crofts would be sent to a psychiatric facility as there were concerns for his mental health, Petersen-Crofts said: "I was painting a picture of Jesus and stayed there for two months".

The boy and his mother were found dead inside the home and the teenage girl was found critically injured in the backyard but died on the way to hospital, police say.

Police were initially called about 1.30am on Sunday to a convenience store on The Broadway before they went to the home.

Assistant Commissioner Paul Steel told reporters in Perth on Sunday, a senior homicide squad investigating officer had said it was "potentially the most horrific crime scene he has ever been called to".

A police officer has called it the most horrific scene he’s been too. Source: 1 NEWS