Charmaine McLeod, 35, was killed with her four children after she drove into an oncoming truck while overtaking on Bunya Highway near Kumbia.
Homicide detectives are now investigating whether the horror crash that claimed the lives of a mum and her four young children in Queensland was a murder-suicide.
Queensland Police Commissioner Ian Stewart confirmed homicide detectives had been brought in to investigate the Monday night crash involving mum-of-four Charmaine Harris McLeod and her four children, Aaleyn, 6, Matilda, 5, Wyatt, 4, and Zaidok, 2.
Stewart said the family's deaths hadn't been added to Australia's national road toll yet and that there were particular rules that determined a traffic crash.
"There are very different rules, and that's why we now have homicide detectives working on this case, where there is a potential that there is an intention for someone to die," he said.
This week on Queensland roads has been the deadliest of 2019 with 12 lives being claimed on the state's roads.
The worst crash was the McLeod family crash when the car the 35-year-old mum was driving slammed into another truck, killing herself and her children, near Kumbia, northwest of Brisbane.
Homicide detectives and specialist forensic crash officers will continue to work at the scene to investigate the fiery Monday night crash.
Police are also questioning why the 35-year-old mum was driving three hours away from the family's home in the Hervey Bay suburb of Eli Waters.
Preliminary investigators also told The Courier-Mail yesterday they were unable to find any skid marks on the road.
Road Policing Command superintendent Dave Johnson yesterday said Queensland Police were conducting a "thorough investigation" in the horrific crash.
"There is a further investigation to determine the positioning of the vehicle and why it was on the road at the time and where it was and what other circumstances, if any, are known to police in that matter," Mr Johnson said.
"Police are doing a very thorough investigation and putting a lot of resources towards that as everybody in this room knows, it was a tragic circumstance for all those involved at the scene and for all those first responders that attended the scene as well.
"It was absolutely horrific carnage that they came across and the loss of innocent lives."
Police did not give a timeline on when their investigation would be finished but said it was a "priority".
"There's a number of police involved in the investigation at various levels and various specialist groups and they're looking at all angles of the investigation and at what's caused that crash to occur."
Speaking to the Daily Mail, Ms Harris' ex-partner James McLeod said he was waiting for the police to finish their investigation.
"Once the police investigation is done the story is going to explode again," McLeod said.
"I just want to wait for the facts and the police are going to report the facts."
McLeod said they had no family or friends in the area where the crash occurred.
Paramedics had to fight their way through flames and smoke to reach the vehicle, which was set ablaze along with the truck.
Rescue workers managed to pull out one child, a girl who suffered horrific burns, but there was nothing they could do to save the others.
Ambulance Service Assistant Commissioner Stephen Zsombok told AAP paramedics faced a daunting scene, with victims trapped inside the burning car.
"These are very seasoned officers and they've explained this as tragic, extremely traumatic with people obviously involved in the car that's caught fire," he said.
"Smoke, fire, our officers have gone though that dangerous scene to get to the child they were able to work on … Unfortunately that child died.
"Our hearts go out to the family and friends of those people."
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