Rowan Baxter and his three children died at the scene in the suburb of Camp Hill, while Hannah Baxter, 31, died later in hospital

This article is more than 6 months old

This article is more than 6 months old

The 31-year-old woman who suffered “horrific” burns in a fatal car fire that took the lives of her three children has died in hospital in Brisbane.

Hannah Baxter passed away at the Royal Brisbane and Women’s Hospital on Wednesday night less than 24 hours after the incident, which is being treated as a possible case of family violence.

The children – Laianah, four, Aaliyah, six, and Trey, three – died in the car after it burst into flames on a quiet suburban street in leafy Camp Hill, in Brisbane’s east, on Wednesday morning during their regular school run.

Hannah’s estranged husband Rowan Baxter, 42, who was at the scene also died, after reportedly stabbing himself.

Hannah Baxter had managed to get out of the burning car, but was on fire.

But Queensland Police said it was too early to tell whether it was a murder-suicide, although one witness said Baxter had run from the car screaming, “He’s poured petrol on me.”

Detectives are still trying to establish how the fire started.

Facebook Twitter Pinterest Police attend the scene of the car fire which claimed the lives four people in Brisbane. Photograph: Dan Peled/AAP

“How the fire actually occurred has not been ascertained at the moment, so for us to call it a murder-suicide or a tragic accident, it’s inappropriate at this stage,” Detective Inspector Mark Thompson said.

“I’ve seen some horrific scenes … It’s a terrible thing to be presented with.”

Neighbours reported hearing multiple explosions before seeing the SUV engulfed in flames in Raven Street about 8.30am on Wednesday.

Neighbour Murray Campbell said he heard a number of loud bangs.

“It was just horrible, multiple explosions, very loud,” he said.

A man who tried to help at the scene was also taken to hospital with facial burns.

The Baxters owned a fitness business called Integr8 and are believed to have separated before Christmas last year. The family was not involved in any family court or federal court proceedings.

Baxter was a member of the New Zealand Warriors NRL squad in the mid-2000s but did not play a first-grade game. His estranged wife was a trampolining champion.

Baxter’s Facebook page is littered with pictures and videos of the three children and comments like “loves them to the moon and back” and “daddy misses you all”.

Six days ago a friend posted: “Chin up brother everything will work out just hang in there my bro a lot of people care about you and the situation your facing.”

Childhood Domestic Violence Australia CEO Tracy McLeod Howe said it was a tragedy.

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In a statement on Wednesday afternoon police confirmed Hannah Baxter, 31, suffered “significant burns” and was transported to the Royal Brisbane and Women’s Hospital in a critical condition.

Rowan Baxter was declared dead at the scene after responding emergency crews attempted to revive him.

“Preliminary investigations indicate the woman was driving the car and the man was in the front passenger seat prior to the incident,” police said in a statement.

“A man who assisted in rescuing the woman from the vehicle sustained burns and was transported to the Royal Brisbane and Women’s Hospital for treatment.”

Witnesses reportedly described hearing a number of explosions and screams after the blaze broke out. The Courier Mail reported the suburban Brisbane street had been blocked by crime tape at both ends, with police surrounding a car wrapped in orange plastic.

Neighbour Murray Campbell said he heard a number of loud bangs which sounded “very much like a gas cylinder explosion”.

He said he called triple zero, and did not see anyone run from the car, which was engulfed in flames.

Earlier, Queensland’s police minister, Mark Ryan, briefed parliament about the incident and confirmed that the victims included children.

“[It is] a horrific incident,” Ryan said.

“The situation is at a very early stage and I am informed that police are investigating all of the circumstances surrounding this tragic set of events.

“My thoughts are with all of those affected by this terrible tragedy.”

An ambulance spokesman said a passerby suffered minor burns after trying to assist the victims.

“As far as I’m aware, somebody did step in to try and help that was close by,” he said.

“That’s the only detail I know at the moment. He was treated for some minor burns to his upper body. They’re not life-threatening.”