Police probing 11yo Brisbane girl's death

The circumstances leading to the violent death of a Brisbane schoolgirl and her mother's apparent suicide are still being pieced together by police.

The body of 11-year-old Celeste Pearson was found in the bathroom of her family's Auchenflower unit by police who had been called to conduct a welfare check early on Tuesday morning.

Hours later passers-by found the body of her 49-year-old mother, Chiaki Pearson, at a construction site in nearby Toowong.

The site and the family home have both been declared as crime scenes.

Celeste's father was questioned by police at length on Tuesday but was released without charge.

He told police he had been asleep and didn't know the girl was dead until he was woken by officers.

Police are still considering the possibility of a murder-suicide, but are keeping an open mind.

Celeste's death has shocked and saddened her classmates at Milton State School, where she attended as a Year Six student.

Principal Paul Zernike said support was being provided to students and staff.

"She was an enthusiastic, high-achieving and friendly young child who will be greatly missed by all her friends and teachers," he said in a statement.

Celeste's eight-year-old sister is being cared for by family and friends.

Readers seeking support and information about suicide prevention can contact Lifeline on 13 11 14 or Suicide Call Back Service 1300 659 467.