Detectives began piecing together what they could about the weeks leading up to the alleged murders – the second filicide in NSW in as many months,aftera two-year-old was killed by his father in the Northern Rivers in May during a custody visit.

In that case there was an apprehended domestic violence order. This father,who is in an induced coma and under police guard,had no criminal history. There was no ADVO. Police did a welfare check last week but would not say who called them;it was not neighbours nor the children. Officers were told all was fine.

But neighbours and friends say the father had been behaving erratically of late,particularly over the past week. One friend said he had been “very chaotic” while he was dropping the older siblings at their local public school,and appeared aggressive and angry with the children.

A neighbour saw him in their people-mover van,roaring dangerously up the street. He did not have full-time work,and the family lived in social housing. He struggled with the workload from the family,one said.

One neighbour said he used to pay the father $50 to mow the lawn. He’d take the money and say nothing. Another said he’d often stand in the front yard wearing shorts,impervious to the cold with skin “like a ghost”,they said. “He seems angry a lot.”

The man shared many of the characteristics raised this month by Australia’s National Research Organisation for Women’s Safety (ANROWS),which this month released the most comprehensive snapshot of filicide,a crime that claimed almost 140 young Australian lives between 2010 and 2018.

Most perpetrators were men (68 per cent). Of those,most were between 20 and 29 (44 per cent). Most lived with their victims. Of the male offenders,most were the biological fathers. More than half did not have full-time work,and were noted to be experiencing mental health issues at the time of the murders.

In three-quarters of cases there was no evidence of pre-planning.

Three in five families had been in contact with child protection services (it is not known if this family was among them) and while many perpetrators had interacted with police,the contact was often in the distant past (this alleged offender only had contact with the legal system over tax and traffic matters).

Many families had also had recent contact with health and education services.

Almost one-third of victims were less than a year old,and 70 per cent were five or under. Of the babies under one,69 per cent died in their first five months. “They’re at their most vulnerable,they rely so heavily on caregivers,” said ANROWS chief executive Tessa Boyd-Caine.

One veteran police specialist told the researchers that they had often been involved in cases involving the death of a baby in the months after its birth.

The challenges of those months could exacerbate pre-existing problems. “While not diminishing responsibility,the challenges and impacts on a person’s conduct … and general coping mechanisms may be intensified if there is existing DFV[domestic and family violence] in the relationship,” the officer told the researchers.

Boyd-Caine said the report showed that health and education services,including early childhood care,were key to identifying and alerting others to the warning signs.

“There’s good evidence about using the places people trust,” she said. “These are the points of connection[with families],where we build an understanding of how to check if someone is safe,and what can you do about it if they’re not.”

The members of the family cannot be identified for legal reasons.

If you or someone you know is affected by sexual assault,domestic or family violence,call 1800RESPECT on 1800 737 732.

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