A vigil to remember "beautiful little girl" Sophia Rose near Bundaberg in southern Queensland was held before locals heard the tragic news of her mother Lauren Ingrid Flanigan's death.
Queensland Premier David Crisafulli on Monday said "some explanations" were needed over the Brisbane death in custody, with a review underway.
Emergency services found Sophia outside a home with several stab wounds on May 26 and she died at the scene.
After being charged with her daughter's murder, Flanigan was found unresponsive in her cell at Brisbane Women's Correctional Centre on May 30.
The 32-year-old had suffered a "medical emergency" in her cell before being rushed to Princess Alexandra Hospital in Brisbane where she died two days later on Sunday.
Queensland Corrective Services on Monday said a report would be prepared for the coroner, describing it as "standard practice for all deaths in custody".
Mr Crisafulli said questions needed to be answered in a "full and thorough" investigation into Flanigan's death to ensure the incident was not brushed "under the carpet".
"This incident proves that there are some explanations that are needed," he told reporters on Monday.
"We owe it to everyone involved, people who work in the facility, families of people who have tragically lost their life, to get to the bottom of it."
He said the corrective services system needed to be reviewed in the wake of Flanigan's death.
"For those who do need to be held in custody, we have a duty to provide safe facilities," he said.
"I think it's important that we don't brush it under the carpet."
The Moore Park Beach community is grieving after coming together to celebrate Sophia on Sunday.
Hundreds came dressed in pink and with sparkles, Sophia's favourite things, at the gathering organised by Bundaberg local Trish Mears.
Sophia was remembered for her love of dance and a child who had an "absolute love of life".
"She was just a beautiful little girl who was just full of life and lit up a room when she walked into it," Ms Mears told AAP.
Friends, family and supporters blew bubbles and wrote messages in the sand while Sophia's favourite song, "Sky Full of Stars" by Coldplay, played.
"It was absolutely beautiful and I could certainly feel her spirit there," Ms Mears said.
The vigil aimed to kickstart the healing process for the grieving community with many attendees who did not know each other sharing hugs and kind words, Ms Mears said.
But the news of Flanigan's death ensured Sunday ended on a "tragic" note, she said.
Ms Mears, the president of Moore Park Beach Arts Inc, said the community would also honour Sophia at their local festival in August.
A GoFundMe set up for Sophia's father and siblings has so far raised $55,000.
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