'Selfish': Grieving dad lashes out at mum after four children killed in crash

James McLeod says his former partner's actions were a 'selfish, pointless act'. Photo / Channel 9

The father of four children killed in a fiery Queensland car crash, has slammed the kids' mother's alleged actions as a "selfish, pointless act".

Homicide detectives investigating the tragic roadside death of a mother and her four children last month are looking at a handwritten note and other clues that could confirm the fatalities were a deliberate act by the children's mother, Charmaine McLeod.

Ms McLeod, 35, was behind the wheel of her Nissan station wagon on the evening of May 28 when it overtook one truck, before colliding into another on the Bunya Highway, near Kingaroy.

The truck flipped before both vehicles burst into flames on the roadside.

She died, alongside her four children Aaleyn, 6, Matilda, 5, Wyatt, 4, and Zaidok, 2.

Charmaine McLeod and her four children, Matilda 5, Ally, 6, Zaidok, 2, and Wyatt, 4. Photo / News Corp

Now, her former partner and the father of the children, James McLeod, has broken his silence.

He told Channel 9 that hearing the news that his children had been killed was the "worst news I'd ever endured".

"They were all I lived for," he said. "Now I've got nothing.

"I'm just absolutely gutted, that someone I trusted and loved could do that to them. I don't know why she did this. It's just a selfish, pointless act."

The couple had been separated for two years and, in that time, they had argued over who the children would live with.

Mr McLeod released a statement after the death of his wife and children, saying he loves them "very much, and they will be surely missed with all of my heart".

"They were beautiful souls and were loved by all who knew them," Mr McLeod said.

According to a report by The Courier-Mail, Mr McLeod started asking questions about what his wife and four children were doing out near Kingaroy, more than three hours from their family home.

Charmaine McLeod and her four children were killed in a car crash near Kumbia, Australia. Photo / News Corp

According to the newspaper, Mr McLeod claimed his wife had "no relatives or family out that way" where the crash occurred.

As well as the alleged note, forensic investigators also failed to observe any brake marks at the scene of the crash, suggesting Ms McLeod hadn't tried to stop the car.

The public have also drawn attention to the mother-of-four's unusual online activity leading up to her death.

One of the first police officers on scene told reporters it was one of the "worst accidents I've ever seen".

"This is a catastrophic incident," he said.

"It was a high-speed impact that caused the heavy vehicle to roll over and the woman's car has caught fire."