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Police say they now know exactly how a 16-month-old Northland baby got his fatal injuries several days before he died in Auckland's Starship Hospital.
However, they said today the homicide inquiry into the death of Riley Justin Osborne, was at a "crucial" stage and no further information could be released.
They also said they were very confident they would solve the case.
The toddler died on Tuesday, four days after he had been flown from Kerikeri in Northland.
Police earlier described the injuries as "non accidental" and "horrific".
They said today after a post mortem in Auckland, they now knew how the baby got the injuries.
"We are very, very clear on that point," Inspector Marty Ruth from the Whangarei CIB said.
He would not say if police were looking for a weapon but said they were confident the case would be solved.
"We are very confident we are going to bring this to a conclusion. Things are moving along quite nicely."
He would not talk about the possibility of an arrest or charges.
"Our evidence is coming in from experts and different things and we are just weighing up our options in terms of where we go.
The infant lived with his 22-year-old mother, 21-year-old stepfather and a family friend in a unit in Kerikeri.
- NZPA
