Nelson police say they are frustrated by a family's silence about who caused skull and brain injuries to a four-month-old baby boy at Labour weekend.
Police are beginning to reinterview people who were in the Motueka house between Sunday afternoon and Monday night, when they believe the baby was assaulted.
Detective Sergeant Kevin Tiernan says although the family has been partly cooperative, someone is withholding information.
The baby was expected to be released from hospital on Thursday and placed in the care of Child, Youth and Family while investigations continue.
The extent of his brain injury will be monitored by specialists.
