KEY POINTS:
The older brother of a critically injured baby has been seized by authorities as the children's teenage parents are investigated by police.
A spokeswoman for Child, Youth and Family Services last night confirmed it had taken custody of an 18-month-old boy whose 4-month-old brother is fighting for his life.
The spokeswoman said CYFS had taken legal custody of both children pending a plan for their safety and well-being.
Detective Inspector John Tims said the boy - who lived with his parents, maternal grandmother and 18-month-old brother - this morning remains in a critical condition.
The parents of the injured South Auckland child yesterday gave police statements about what happened on the night their baby was injured.
Spokeswoman Senior Sergeant Denise Traill said the 18-year-old mother and 19-year-old father had given police initial statements and were co-operating with police.
However, details of how the baby suffered life-threatening head trauma on Saturday night have not yet been made public.
Ms Traill said it was "too early" to know what the situation was at the Papakura state home, whether a party had been held there or how many adults were present at the time the boy was injured.
All that has been made public is that an ambulance was called to the house at about 9.30pm. The badly injured baby was taken to Middlemore Hospital before being transferred to Starship where he underwent surgery on Sunday.
"We want to acknowledge the family are co-operating with us," said Mr Tims last night. "The parents are at their son's bedside and we are working with them."
CYFS deputy chief executive Ray Smith said the organisation was working with the family to ensure ongoing safety of the baby.
"The injuries suffered by this baby boy are a tragedy, and our condolences and sympathies go out to his family and loved ones.
"We are working with the family and other agencies to ensure his ongoing safety and to provide the family with the best supports possible to help them through this challenging and devastating time."
Mr Smith said it was important speculation and comment were kept to a minimum so police could "get on with the job of bringing to justice those responsible for this baby's injuries".
Mr Smith said CYFS had not previously been notified of any concerns regarding the baby. It was unclear whether the family had come to the organisation's attention in regards to other children such as the older brother.
Meanwhile, a scene examination of the boy's home is due to continue today.
A specialist child abuse investigative team, assisted by an Environmental Science and Research specialist, spent most of yesterday at the home, where bottles and rubbish lay on the unmowed lawn.
