The chief coroner has confirmed he is to hold an inquest into the death of the Kahui twins.
The babies died of traumatic head injuries in June 2006, and their father, Chris Kahui, 23, was acquitted of their murders in May this year.
Police have said there can be no further arrests unless new information comes to light.
Chief coroner Neil Maclean says a coronial inquiry will look at matters wider than criminal guilt to try find answers the criminal investigation did not.
The inquest likely to be held in October.