Detectives who initially thought a shed fire at a rural Queensland property that killed a groom-to-be and his 10-year-old daughter in a tragedy days before Christmas are now investigating the case as a homicide.

Todd Mooney, 54, and his daughter, Kirra, 10, were killed in a fire at their property outside Biggenden, about 240 kilometres north of Brisbane, on December 20.

Kirra’s mother and Mooney’s partner, Rebecca Hansen, who worked alongside Mooney at their bakery, came home to the grim discovery after a call from a neighbour alerting her to the fire.

The pair were due to get married on Wednesday this week.

Forensic specialists and detectives were continuing to comb through the crime scene, with Detective Chief Inspector Gary Pettiford saying the investigation had taken some time because asbestos had been found in the shed.

Pettiford said initial investigations did not suggest anything “untoward” had happened at the property.

But now, detectives were considering Mooney’s and Kirra’s death a homicide.

“We’ve now reached a conclusion where this hasn’t been a tragic accident. We believe that the fire was deliberately lit,” he said.