Police officers involved in a stand-off with a gunman who had already shot three civilians - killing two of them - acted appropriately by firing at him, a review found.
The Independent Police Conduct Authority (IPCA) has released a report into the incident involving Northland man Quinn Patterson, who fatally shot two women and injured a man when they approached a property he was living at in July last year.
Mother and daughter Wendy Campbell-Rodgers and Natanya Campbell were killed.
Patterson's body would be found in the later burnt-out house afterwards. A post-mortem found he had most likely shot himself before the fire - which he started after a shoot-out with police - reached him.
Authority chairman, Judge Colin Doherty, said: "Police responded swiftly and professionally to an extremely serious and tragic incident.