Dad questioned over Qld 11yo's death

The father of a schoolgirl who died violently in a Brisbane flat is at the centre of the police investigation into her death and that of her mother.

The 11-year-old was discovered at her family home in Auchenflower early Tuesday morning, with her 49-year-old mother found dead hours later by passers-by outside a block of flats in nearby Toowong.

Queensland Police Detective Acting Superintendent Geoff Sheldon said the father had not been charged but was being held in custody while he helped police piece together the events surrounding the two deaths.

"That's the actual crux of the whole investigation - has this man committed any offences that would warrant him being arrested," he said.

"At this stage, he's helping us and that might not necessarily be the case."

Police are still considering the possibility of a murder-suicide, with Det Supt Sheldon deeming it unwise for police to have a closed mind either way.

"We're not rushing these things - we'll probably have that crime scene for three days," he said.

He also revealed police were called to the family home once in the past six months over an allegation of domestic violence, but no action was taken.

Police were called to the flat shortly after 1.30am after family friends contacted them over concerns for the family and discovered the girl's body.

The father, who said he had been asleep, did not know the girl was dead until he was woken by police.

Worried officers launched a search for the mother only for her to be found dead some four hours later.

The mother and her two children, all born in Japan, lived together with their father at the suburban unit and were described by Det Supt Sheldon as a typical family.

The second daughter was not at the flat and is unharmed.

Police are working to find extended family overseas.

* For support and information about suicide prevention, call Lifeline on 13 11 14 or Suicide Call Back Service on 1300 659 467