The grandmother of a six-month-old Ngaruawahia girl who died a violent death says someone needs to come forward with the truth.

Serenity Jay Scott-Dinnington was admitted to Auckland's Starship Hospital on Tuesday last week. She died two days later, after her life-support was switched off.

Senior Sergeant Mark Greene, in charge of the homicide inquiry, said provisional post mortem examination results showed Serenity died from traumatic brain injuries.

"I would stress at this stage that the post mortem results are only provisional, but they give us some idea as to what sort of injuries she suffered during what was obviously a very violent death," Mr Greene said.

Grandmother Celeste Scott said her daughter loved her kids to bits and was a dedicated mum.

"What happened? How? When? Who? It's all the same questions over and over...I've got no answers.

"The sooner the better, then everyone can start to breathe and sleep properly without having nightmares and bad thoughts and it will also stop mouths bleating a whole lot of rubbish," Ms Scott told One News.

A neighbour, who wanted to be called Cheree, called an urgent community hui today to discuss child abuse, though police said it would not help their inquiries.

"I believe there should be some accountability for a baby's death. It takes a community to raise a child -- this community will show we can keep raising children," Cheree said.

Waikato police were continuing investigations and were speaking to the baby's family and neighbours.

Her body had been returned to her family and a funeral was expected to be held this week.

Family have been told by medical staff and police they believed her injuries were similar to shaken baby syndrome.