A four-month-old Aboriginal baby girl has tragically died after her mother was arrested at a public housing unit in Katherine on Sunday.
The 21-year-old mother was still in police custody when her daughter died.
On Wednesday the Northern Territory Police released a statement saying it would undertake an investigation into what happened.
"A 21-year-old woman had been taken into police custody before the child's death was reported to police.
"The matter is still under investigation and a full report on the circumstances will be delivered to the coroner."
Northern Territory Children's Commissioner Colleen Gwynne told the ABC she was undertaking preliminary enquiries into the incident.
"The children's commissioner is aware of the tragic death of the baby in Katherine and received a briefing on Wednesday morning," the Commissioner said in a statement.
"The commissioner has formally requested further information and is undertaking preliminary enquiries including a review of family history and interactions with services."