An ex-rugby league player is suspected of killing his three children and estranged wife by setting fire to their car, in what Australian police described as one of the most horrific incidents they have encountered.
Police said a 31-year-old woman, named by local media as Hannah Baxter, died in a Brisbane hospital on Wednesday just hours after her three children aged three, four and six were found dead in the burned car on a suburban street.
Her estranged husband, Rowan Baxter, who also died, allegedly approached the car and doused it with petrol before setting it alight, The Australian newspaper reported.
The paper said that she jumped from the burning car and rolled on the ground, saying "He's poured petrol on me".
Officials said she was rushed to hospital with severe burns following the "horrific" incident but later succumbed to her injuries.
Public broadcaster ABC reported Baxter, a 42-year-old former Rugby League player for the New Zealand Warriors, was in the burning vehicle but got out and died on the footpath.
Other reports said he died of a self-inflicted knife wound.
The tragedy led to an outpouring of grief on social media, with many calling for stronger action to address domestic violence.
Natasha Stott Despoja, a former senator and chair of anti-violence group Our Watch, called violence against women in Australia a "national emergency".
"I know people want change, people are angry & sad today," she tweeted. "How long before we stop this slaughter in our suburbs?"
Police are treating the area in Brisbane's inner east where the incident occurred as a crime scene but said it was too early to speculate on the cause of the fire.
"How the fire actually occurred has not been ascertained at the moment," Queensland Police detective inspector Mark Thompson said Wednesday.
"For us to call it a murder-suicide or a tragic accident, it's inappropriate for us to try to do that."
"I've seen some horrific scenes. This is up there," Thompson said.
A passer-by who tried to intervene in the situation was also taken to hospital to be treated for facial burns, a Queensland Ambulance Service spokesperson said.
"Somebody did step in to try and help that was close by," he told reporters at the scene.
"He was treated for some minor burns to his upper body. They're not life-threatening."
The emergency services who responded to the scene have been stood down from their duties and will receive support, he added.