A woman who was found dead inside a Logan house gutted by fire had gained entry to her former partner's home before petrol was "thrown around", Queensland police say.
Fire crews were called to the property on Bidyan Boulevard at New Beith just before 3am where they discovered the body of a 31-year-old woman who did not live at the house.
A 30-year-old woman escaped the house without injury and was taken to the Royal Brisbane and Women's Hospital for observation.
A 33-year-old man, also from the residence, sustained critical burns to most of his body and was taken to hospital.
Police Superintendent Mark White said the woman who died and the man were formerly in a relationship.
He said there had been a previous domestic violence investigation into their relationship.
Authorities said the low-set home was "engulfed in flames" and the roof had partially collapsed, in a blaze police said was "suspicious".
Superintendent White said the deceased somehow gained entry to the home and petrol was thought to have been "thrown around".
Collapsed roof poses challenges for forensic teams
Superintendent White said while the investigation was in its early stages, he asked anyone who knows the family or the deceased woman to contact CrimeStoppers or the Logan District CIB.
"We've not been able to interview the lady ... who [was] fortunate enough to escape and so we are also appealing to any members of the public who were in that area," he said.
"We would like to talk to them because we want to endeavour to establish what has occurred there last night and also any background information that may assist with the investigation."
Superintendent White said the partially collapsed roof was causing problems for officers.
"The crime scene has been declared and as I've stated, the structure itself is in a very fragile state and that is making the forensic examination very difficult," Mr White said.
"Also it is making it difficult for the deceased person, who was still in that residence, to be removed."
