The teenage father who allegedly bashed his 28-day-old son had a troubled past, including assaulting his 16-year-old partner, Western Australia's Department for Child Protection has revealed.
The baby suffered critical head injuries in the assault at Bunbury Regional Hospital on Saturday night, and is on life support at Princess Margaret Hospital.
The baby has been taken into the care of the Department for Child Protection, leaving chief executive Terry Murphy to make all medical decisions.
The 15-year-old father - who himself was under the care of the state - has been charged with aggravated grievous bodily harm.
WA Minister for Child Protection Helen Morton said the baby had been in hospital since his premature birth.
The assault occurred when the mother left the room to heat up some food during a visit, a day or so before the infant was due to move into her family's home.
Ms Morton said the department did yet not know the exact circumstances before the incident, but that would be reviewed.
She said the teen had previously assaulted his partner after being abandoned by his mother at age 12.
There were no restrictions on his access to the child.
"From the day the baby was born, he was a regular visitor to the baby, he was involved in the feeding and the baby's management," Ms Morton said.
"Via the hospital staff, the Department of Child Protection and the family, it was agreed that he would visit during visiting hours. That was unsupervised."
Mr Murphy said the incident could not have been foreseen.
"From this boy's previous behaviour, both as a child in care of the department and, more specifically, what had transpired since the baby was born, this could not be predicted," he said.
"Over 30 midwives saw the baby and the parents.
"We do not know what occurred."
