Brisbane stepmother charged with murder over disabled four-year-old's horrific death

Police have arrested the stepmother of Brisbane girl Willow Dunn and charged her with murder after the four-year-old's severely malnourished body was found at a Brisbane house last week.

Her father, Mark James Dunn, 43, has already been charged with her murder and today police confirmed they had also arrested and charged Willow's stepmother with her murder.

Shannon White, 43, has had her charge mentioned but was not brought into court when the matter was brought before Brisbane Magistrates Court on Wednesday afternoon.

Detectives will continue to investigate the health, care and treatment of Willow, who had Down syndrome, in the days, weeks, months and years before she died.

"We have initiated investigations and inquiries in New South Wales, and in particular, we have advanced investigations that will continue and progress in South Australia," Detective Inspector Chris Knight said.

Willow Dunn

South Australia's major crime squad is involved.

The little girl's family moved from South Australia to Brisbane in 2017.

Police were faced with an "extremely confronting" scene at the home where Willow's body was found, with a post mortem finding she had suffered sustained mistreatment and had a litany of injuries.

Her death is being investigated by Cheryl Vardon, who leads the Queensland Family and Child Commission, to determine whether Queensland's child safety system failed.