Police have alleged father Charlie Hinder, 38, used explosives to kill himself and his two children in a caravan in north-west Queensland last week.

Eleven days after the explosion, police said the deaths of the two children aged seven and four were being treated as suspicious, but not that of their father.

• Two people found dead in car
• MH370: ‘Aircraft seat cushions, window panes found’

More than 55 nearby households were evacuated after the blast as debris flew more than 50 metres away.

Investigators thought the explosives were used as an ignition point in the incident, rather than gas bottles found at the scene.

River, Charlie and Nyobi Hinder died in the blast. Photo: ABC

They believed no one else was involved.

Mount Isa District Officer Superintendent Russell Miller said they were trying to identify what was used to cause the explosion.

“We haven’t been able to identify that at this stage but certainly, at this point in time, we’re looking at some sort of explosive device or equipment that has caused it,” he said.

“It has occurred inside the caravan. The explosion has occurred inside the caravan, not outside.”

Superintendent Miller said the explosion had devastated the local community.

“This was a horrific event which has had a significant impact not only on the families, neighbours and friends of the victims, but also the wider Mount Isa community,” he said.

“At this time we appeal to the community to respect the privacy of the immediate and extended members of the Hinder families while they come to terms with this tragedy.”

Superintendent Miller said investigators would continue to work closely with the state’s northern coroner on the matter.

Police have previously said it could take weeks, if not months, to fully complete the investigation.

– with ABC and AAP

For support and information about suicide prevention, call Lifeline on 13 11 14; Suicide Call Back Service on 1300 659 467 or MensLine Australia on 1300 78 99 78.