Mum suspected Mt Isa explosion was murder

The mother of two young children killed in a Queensland caravan explosion is "resigned to the fact" their father murdered the children and took his own life.

Police are treating the deaths of Nyobi, 7, and River, 4, as suspicious, 11 days after the explosion in front of a Mount Isa home.

But the death of the children's 38-year-old father, Charlie Hinder, is not suspicious and no one else was involved in the tragedy.

Police say news of a double murder-suicide investigation confirmed the suspicions of the children's mother.

"She was resigned to the fact," Mount Isa District Officer Superintendent Russell Miller told AAP on Friday.

"The lady's still quite grief-stricken and still struggling to come to grips with it all."

Bomb experts have determined explosives, and not gas bottles, were used in the powerful explosion that shattered windows 60 metres away and flung debris along suburban Deighton St.

They also believe the ignition came from inside the caravan and have found traces of explosives on evidence taken from the scene.

Mr Hinder's Facebook page has been investigated amid rumours a goodbye letter had been posted.

The mother was inside the house when the caravan exploded and made a lucky escape as the roof caught alight.

A neighbour told the ABC a woman was seen crying and saying "there's blood, there's blood" as the dwellings burned.

Mount Isa Mayor Tony McGrady says the latest development will shock a town already dealing with trauma.

Corner store owner Kev Spanner, who knew the children's mother as a teenager living behind his shop, used to chat to Mr Hinder when he bought milk.

"He wasn't massively down but he was down all right," Mr Spanner told AAP.

"He said, 'I'm having it rough at home.'"

Supt Miller said the coroner would have to release remains before family could bury their loved ones.

He confirmed the investigation could take months and said investigators had not identified a reason for Mr Hinder to kill the children.

"Who could come up with a reason for those sort of actions?" he said.

* For support and information about suicide prevention, call Lifeline on 13 11 14.