Queensland Police is now treating the deaths of a man and his daughter as a homicide, believing a third party was involved in a fire in a North Burnett shed where the pair's remains were found last week.
The bodies of Todd Mooney, 54, and Kirra Mooney, 10, were discovered by fire crews in the burnt-out shed in Biggenden on December 20.
State Emergency Service (SES) volunteers are searching the area for evidence, including possible weapons.
Detective Chief Inspector Gary Pettiford said the forensic examination of the bodies had prompted police to upgrade the investigation to homicide.
"Originally, we thought this was a terrible, tragic accident," he said.
"We [now] believe that the fire was deliberately lit and, as direct consequences of that, the two people have passed away.
"It's gone from a terrible tragedy to a horrific homicide involving a little 10-year-old girl and her father."
Detective Inspector Pettiford said he was "very shocked" by the change in investigation from accident to homicide.
"There was no indication initially that anything untoward had happened," he said.
Detective Inspector Pettiford said investigations had "not concluded yet".
"We're looking for anything – whether it be a firearm, a knife – just anything unusual that may have been thrown into the grass," he said.
"We believe there is a third party involved."
SES North Burnett controller Brian Lowe said 22 volunteers were part of the forensic search team.
"We look for something that shouldn't be there — possibly a knife, a gun, an iron bar. We don't know … there's a lot of questions unanswered."
Due to be married
Detective Inspector Pettiford said Mr Mooney's partner and Kirra's mother Rebecca Hansen was at work at the time of the fire and was "distraught".
"Todd was the local baker out here, and Bec worked in the bakery itself," he said.
"She was actually due to be married yesterday to Todd.
"She's obviously distraught, not just losing her partner, but her 10-year-old daughter."
Plea for public assistance
Detective Inspector Pettiford said police were "really interested" in help from the community.
"We're appealing to members of the public in this local area to come forward if they do know anything about this incident," he said.
"We're also looking for any dashcam [footage] that might be available from motorists that were travelling between Biggenden and Mundubbera on December 20 between 10:00am and 2:00pm."
Detective Inspector Pettiford said the investigations were ongoing.
"Our forensic side of things have physically finished here on scene, so they left yesterday afternoon," he said.
"There's a lot of work to be done in the laboratories in Brisbane.
"We spend days out here shovelling the remainder [of the shed] and hand-sifting all the debris. That's taken quite a while."
