Detectives investigating the death of Northland 1-year-old Atreyu Taylor-Matene have issued a description of a woman they want to question.
The woman was seen on Carlton Cres in Kamo, Atreyu's hometown, about 10am last Friday.
Atreyu was admitted to Whangarei Base Hospital that morning before being flown to Starship Hospital in Auckland, where he died that evening.
The woman is described as aged about 20, dark-skinned, slim and about 1.65 metres tall.
She had dark hair tied back and was wearing a dark grey hoodie, light grey trackpants with two stripes down the legs and black Chuck Taylor-style shoes.
Twenty officers are working on the homicide inquiry and continue to focus their efforts on establishing how Atreyu came to have the injuries that caused his death.
Investigation head Detective Senior Sergeant Kevin Burke said yesterday that police believed only two other people were in the house when Atreyu suffered fatal head injuries, his mother and her new partner.
Ms Taylor shared custody with Atreyu's father, Joshua Matene, and grandparents in Auckland.
Police were still waiting for some results from the post-mortem examination, but it had been established that Atreyu died as a result of significant head injuries.
Detectives attended Atreyu's funeral in Kaikohe on Tuesday, which Mr Burke said was "an extremely moving occasion''.
Investigators had interviewed members of Atreyu's family and others to try and establish how he died.
"It's still good old detective work. We're still continuing working through different accounts and speaking with people that we believe will assist us with the inquiry.''
Mr Burke would not be drawn on Facebook comments that Atreyu's death had been the result of a fall.
"It's an ongoing homicide investigation.''
Atreyu had not come to police's attention prior to this incident.
"From all accounts, prior to this event, he was a healthy, bonny boy,'' Mr Burke said.
Anyone with information should contact Whangarei Police on 09 430 4500, or Crimestoppers, anonymously, on 0800 555 111.