Experts say revenge is one possible reason why a family-of-five is dead after a horrific attack in Brisbane.
Hannah Baxter and her three children died at the hands of her estranged husband and their father Rowan on Wednesday and now questions are being asked about his motivation.
Rowan and Hannah reportedly separated just before Christmas, and were trying to sort out custody arrangements.
Revenge against Hannah is one possible explanation Bond University criminologist Dr Terry Goldsworthy says.
Revenge was one-of-five common explanations for killings that involve a person's children, and were mainly aimed at making the spouse suffer, he said.
"At least on some of the actions that were alleged yesterday we saw examples of that where he didn't want the car (fire) put out," he told AAP.
Laianah, 4, Aaliyah, 6, and Trey, 3, burned to death in the car after it burst into flames on the quiet suburban street in Camp Hill in Brisbane's east.
Hannah, 31, died in hospital overnight after being doused in petrol and set alight by Rowan.
He died on the footpath from self-inflicted wounds, police say.
Queensland University of Technology Professor Kerry Carrington, who is an expert in gender violence, said the "horrific" attack could have been prevented.
"The most risky time for a woman is in fact during the first six months of separation - that's when they're most at risk of being killed by an ex-partner," she told ABC Radio National on Thursday.
"Had we had the kind of supports in place to protect and support women in that period, and we don't have it, then a lot more could have been done."
Hannah joins a worrying number of people killed at the hands of a family member, with advocates from The Red Heart Campaign say 63 women and 23 children died from domestic violence last year.
Prof Carrington said Australia needed to take a more proactive approach.
"We know that these incidents are predictable and because they're predictable they're preventable," she said.
She said Argentina and Brazil had been successful in cutting family violence by implementing a holistic approach that involves lawyers, social workers, police and psychologists.
They intervene at the first sign of any violent behaviour, with offenders sent to special centres for unlearning violence.
Australia needed a huge shift in mindset to address the problem, she said.
Australian Associated Press