The police say a boy had to fight his way out of the fire that killed his father and brother in the Auckland suburb of Bucklands Beach.
A homicide inquiry has now been launched into the 2 October double fatal fire which police say was deliberately lit with an accelerant.
Three people survived the blaze - including the boy and his mother. The victims were believed to be s 36-year-old man and his 11-year-old child.
A fifth person, a boarder at the residence, did not suffer any injuries.
Inspector Tofilau Faamanuia Vaaelua said the family's lives have been shattered.
He's calling for neighbours around Murvale Drive to come forward with any footage they may have from the days leading up to the fire - saying no piece of information is too small.
Detective Inspector Tofilau Faamanuia Vaaelua talking to media about the fire on Wednesday. Photo: RNZ / Marika Khabazi
In a media briefing on Wednesday, Vaaelua said the blaze was well established by the time emergency services arrived at about 2.30am on 2 October.
Police had now confirmed the fire was deliberately lit, he said.
"Three people were able to escape, but sadly two people were not, and were found deceased inside the home.
"I can say the mother of the children and the wife exited the property through the doorway ... The border was based downstairs, but I can say that the third survivor, the boy, had to force his way out of the house."
He said forensic analysis of the accelerant found at the scene was yet to be completed.
"The scene examination of the home was completed on Sunday. However, due to ongoing forensic analysis and potential for revisits to the address, the scene remains under police guard.
"I can confirm the post-mortem examinations have been completed. Further detailed analysis from those post-mortems continues. One victim can be confirmed as the 36-year-old father of two."
"We have not as yet been able to formally identify the second victim. However, we believe that he is the family's 11-year-old son. The two other victims who were hospitalised have now been discharged."
The detective said police were hoping to formally release the names of the two deceased later.
The detective inspector said that currently they had no persons of interest.
"We're casting the net far and wide to collect any evidence of CCTV that might assist us in that space, in that regard."
It was safe to assume the fire was intentionally lit by someone who entered the home while the family were asleep, he said.
The property remains under police guard and officers are keen to speak to anyone with information that may help with their investigation, he said.
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