The family of a nine-month-old baby girl whose body washed ashore on a Gold Coast beach allegedly threw the child into the water across the border in NSW, police in Queensland believe.
Sources familiar with the investigation into the death have told AAP the family of four were tracked on CCTV travelling from the Gold Coast to the Jack Evans Boat Harbour in NSW on Saturday.
It's alleged the naked baby girl was thrown into the harbour and her empty pram left alongside the waterway.
Queensland police then captured images of the now trio catching a bus at Coolangatta and returning to Queensland, sources said.
The baby's body is believed to have drifted in the current for two days before washing ashore at a Surfers Paradise beach where she was found by passers-by at around 12.30am on Monday.
Queensland Police confirmed in a statement on Tuesday night that it had been established the baby's death occurred in NSW but gave no further details.
The child's father, a 48-year-old homeless man, will face an extradition hearing in Southport Magistrates Court on Wednesday. He's expected to be charged by police upon his successful return to NSW.
But it's believed the girl's mother, 23, will not face charges.
Police sources in Queensland allege the mother admitted to knowing about the plan, but only the father would be accused of throwing her into the water.
Police sources have also said the mother has been released from custody and it's understood she has been placed in the mental health system in Queensland.
Queensland police detectives have been "deeply distressed" by the circumstance of the child's death, the sources said.
