Brisbane mother and three children die in a car fire allegedly lit by children's father: What we know so far.

This post deals with violence and might be triggering for some readers.

A Brisbane mother and her three children have died from injuries sustained in a car fire allegedly lit by their dad and husband, who also died from self-inflicted wounds.

Former NRL player Rowan Baxter is accused of dousing the car in flames at 8:30am on Wednesday morning in Camp Hill, while his wife Hannah, 31, and their children Laianah, 6, Aaliyah, 4, and Trey, 3, were inside.

The children died at the scene, but Hannah passed away in the early evening after being taken to hospital with significant burns. Witnesses told the ABC they heard the mother-of-three yelling “he’s poured petrol on me,” as she jumped from the vehicle.

WATCH: A witness talks to The Today Show. Post continues after video.

Another witness told AAP “it sounded like a gas cylinder explosion. It was just horrible, multiple explosions, very loud.”

According to The Courier-Mail, Rowan stabbed himself in the torso at the scene and died from his injuries. The publication also reports that as witnesses rushed to try and stop the flames, he told them: “stop putting it out.”

Detective Inspector Mark Thompson said yesterday: “I’ve seen some horrific scenes – this is up there with some of the [worst]. It’s a terrible thing to be presented with.”

Paramedic Adrian Tong said seven vehicles with first responders and doctors were sent to the scene. Another bystander was also taken to hospital with facial burns after trying to come to the children’s aid.

Police and emergency services were horrified by the tragic scene with first responders given counselling and the rest of the day off.

The family was not involved in any Family Court or Federal Court proceedings, but the Baxters  – who are the owners of Integre8 and CrossFit SMC – had reportedly separated last year, with Hannah and the kids staying at her parent’s house in Camp Hill.

A fundraiser page has been set up by Hannah’s sister-in-law who writes that the family have “exhausted themselves to try and help Hannah escape this monster.”

A member of the New Zealand Warriors NRL squad in the mid-2000s, Baxter had been working at a Brisbane fitness centre with his wife who was a trampolining champion.

Baxter has previously uploaded several posts on his Facebook page dedicated to his kids with captions: "T-R-E-Y Love you to the moon and back," and "Goodnight my babies, Daddy loves you."

Six days ago his friend Joey Abraham wrote under a photo of little Trey: "Chin up brother everything will work out just hang in there my bro."

Photos on Hannah's Facebook show the fitness-focused family doing handstands together - with the kids joining in with burpees and pull-ups with their parents.

"These little weapons! Yep they’re only 5 & 3 years old..Aaliyah asked me if I’d write her up a workout yesterday while Row and I did some comp practice...she said she wanted it to be hard and I thought maybe I’d made it a bit too tough but she proved me wrong and absolutely smashed it.

"Her biggest idol is Tia-Clair Toomey (an athlete) and was even late for prep last year watching Tia win the The CrossFit Games," wrote Hannah in January last year alongside a video of her girls working out in the family's gym.

Police will now investigate the cause of the incident that killed the Baxter family, and have already been searching Mr Baxter’s house for clues as to his state of mind.

Featured image: Facebook.

If this post brings up any issues for you, or if you just feel like you need to speak to someone, please call 1800 RESPECT (1800 737 732) – the national sexual assault, domestic and family violence counselling service. It doesn’t matter where you live, they will take your call and, if need be, refer you to a service closer to home.