A police tent is now outside the Carlton Cres house in the suburb of Kamo, and neighbours are being quizzed on what they might know.
Dakota Witoku, a close friend of Atreyu's mother, told the Herald on Sunday that she didn't know anyone who would hurt Atreyu.
It was a very difficult time for the family, she said.
"They're just trying to get through day by day."
Witoku said she had spoken to Jessica since the accident. "It's just quite hard," she said. "Everyone's still in mourning."
Jessica's father, Donald McGahey wrote on Facebook of supporting his daughter at the police station while she made her statement. He also recounted events leading up to the death.
"Please pray for Atreyu as (he) has been rushed to Starship after a fall," he wrote on Friday.
"Also pray for Jess at this time as she has to deal with the issues around this. She has come down to Starship today, I will be down tomorrow to support her."
Then, on Friday evening: "Atreyu not good at all on life support and may not survive the night, am heading to Auckland within next 30 mins to be with Jess. Please pray urgently for Atreyu and Jess."
Then, four hours later: "Sad news. Atreyu has passed away."
Atreyu's funeral would be held on Wednesday in Auckland, he said.
McGahey declined to comment yesterday.
The family were already in mourning after Atreyu's grandmother, Catherine McGahey, died in April.
Northland acting criminal investigations manager Detective Senior Sergeant Kevin Burke said a scene examination would continue today, with 25 officers involved.
Burke said the injuries would have been caused by "significant force".
He said police were speaking to Atreyu's mother and her partner, and were also interviewing wider family members and neighbours.
"We're working on the fact that the post mortem will be able to confirm the cause of death and also confirm the injuries that were inflicted on the poor little fellow."
Burke said it was clearly a trying time for the family.
"We have to keep an open mind as to where the injuries may have been inflicted. It's early stages and we are treating it as a homicide inquiry."
Police visited residents in Carlton Cres on Friday and yesterday.
One said the death shocked her.
"It's normally quite a quiet peaceful little suburb. I didn't expect anything like that."
Another said police "popped in" the night he died but there was nothing she could tell them.
"We don't see anything much of him, or them, or even know how many live there."
Whangarei mayor Morris Cutforth said it was "out of character" to have violence against children in his district.
