A post mortem was expected to be completed today or tomorrow.
Mr Anderson said there were three adults, two men and a woman, and a nine-year-old child at the house when police arrived.
"We believe the child was close to the scene of the fatal incident and we are speaking with that child as part of our investigation. We are also talking to the female witness to the assault and to wider family members.''
The victim and the alleged offender were known to each other but Mr Anderson would not comment further on the relationship between them as the matter was before the courts.
"Everyone involved is co-operating with police which makes the investigation easier.''
He said police expected to complete the scene examination sometime tomorrow.
The 31-year-old man charged with assault in relation to the incident has been remanded in custody to re-appear in the Whakatane District Court next Wednesday when it is expected more serious charges will be laid.
Neighbours said they were not aware anything had happened until a police car going "a rapid rate of knots'' rushed down the quiet street followed shortly after by an ambulance.
A group of people gathered on Holyoake Cres and spoken to by The Daily Post, none of whom wanted to be named, said they believed a man had been stabbed at a family home.
"I think a group of young ones had been drinking there [or near there] for a couple of days, that's what I was told anyway,'' one man said. "I'm pretty sure the cops were here yesterday as well although I don't think it was for long.''
A resident of Holyoake Cres said he had heard screaming not long before police showed up.
"This is normally a quiet street, we got rid of the loud ones about 18 months ago and there hasn't really been any excitement since then,'' one man said.
Apart from several police cars lining the dark street, the area was deserted and quiet.
While The Daily Post was at the scene, a woman arrived at the home and became distraught after speaking briefly with police. Other friends and family were also gathering outside the address.
Kawerau residents were last night discussing the incident on Facebook.