A Queensland coroner is expected to make recommendations on how police and other agencies respond to domestic violence when she hands down findings in the inquest into the deaths of Hannah Clarke and her children.

Ms Clarke was leaving her parents’ home in Brisbane’s Camp Hill suburb to take Aaliyah, six, Laianah, four, and Trey, three, to school when estranged husband Rowan Baxter jumped into her vehicle on February 19, 2020.

The 42-year-old splashed fuel inside the car and set it alight, before stabbing himself with a knife, dying nearby.

The children’s bodies were found in the vehicle, while Ms Clarke, 31, died the same day in hospital.

Coroner Jane Bentley is due to hand down her findings in a Southport court on Wednesday following a nine-day hearing in March.

She was tasked with investigating Ms Clarke and Baxter’s contact with domestic violence services and counselling, and the response to their contact with such services and Queensland police.

Ms Clarke’s parents Sue and Lloyd Clarke said at the end of the “unthinkably confronting” hearing they hoped the inquest will help others avoid the same fate.

The Coroners Court was told there were systematic failings in police communication and training.

But Mr Clarke said nothing would have stopped Baxter.

“He was just one of those people … so callous and used everyone as a pawn in his monstrous ways,” he said outside court after the hearing.

Sue Clarke added: “Every now and then I think a true monster is born and you can’t stop them”.

Counsel assisting the coroner Jacoba Brasch QC said it was only a matter of time before Baxter killed Ms Clarke once they separated in late 2019, such was his “single-minded, murderous intent”.

“Hannah really was the walking dead the moment she asserted her own independence and left Baxter,” she said.

Queensland Attorney-General Shannon Fentiman says she hopes the legacy of the inquest will be “a much stronger system”. 

“It is incredibly distressing … when we hear about these horrific murders and we have to do more to prevent (them from) happening,” she told 4BC radio on Wednesday.

“I often say we have to start responding to the red flags before more blue police tape surrounds the family home.” 

The inquest was shown CCTV footage of Baxter buying zip ties, cleaning fluid and a fuel can days before the killings.

He also bought three Kinder Surprise chocolates – presumably for his children – when he purchased fuel.

Dr Brasch said Baxter may have initially intended to kidnap Ms Clarke, burn her, then give his children chocolates and it “would all be happy families”.

But he turned to “plan B” once the 31-year-old defied him by asking a bystander for help when Baxter ambushed her, Dr Brasch told the inquest.

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