Blunt force cranial trauma.

That's what killed nine-month-old Maija Puhi-Duff, according to evidence given by forensic pathologist Dr Dianne Vertes.

Vertes was giving evidence via audio visual link from New York State at the trial of Puhi-Duff's father Donovan Michael Duff, 42, who is charged with the infant's death.

Duff has maintained his innocence since being charged with one count of murder over the 2016 death in Turangi.

Under questioning from Crown prosecutor Amanda Gordon, Vertes also revealed she found a number of injuries on the child.

She said she found 14.6 grammes of blood over the surface of the brain - an area where no blood should have been found.

Bruising was also found on Puhi-Duff's jawline, under her nose, on the right side of her neck and both eyes.

Asked for the most likely cause of death, Vertes said "blunt force cranial trauma".

Vertes also dismissed an earlier fall Puhi-Duff had from a bed, and an incident when Duff woke to find he was smothering her, and a fall down some stairs, as the cause of her injuries.

"[They would not cause injuries] in numerous places. . . the scenario does not fit the injuries," she said.

However, on questioning from Duff's lawyer Moana Dorset, Vertes conceded an earlier fall from a stroller could have caused brain bruising.

She stood firm on the question of whether all the injuries being caused by the various falls created a cumulative cause of death.

"Impossible," she said.

"I didn't see cumulative injuries. . . I don't think it's possible.

"The injuries I saw, significant injuries to the layers that cover the brain. . . are all of the same time. Nothing looks like it happened two weeks prior."

Turning to the non-head injuries, Dorset asked Vertes whether it was true that "babies bump themselves all the time."

"Any number of reasons for these injuries?"

"Correct," said Vertes.

After questioning from both lawyers Justice Mathew Down also questioned Vertes, asking for clarification on her view of what caused Puhi-Duff's death.

"She has evidence of multiple blows to the head, and died because of that," she said.

Down also asked whether the injuries would have been survivable.

"No, that's not survivable."

The trial, in it's fourth day at the High Court in Rotorua, began on Thursday with a warning from Down to the seven men and five women of the jury about a book of photographic evidence.

"[The photos] have the potential to be distressing, however the photographs constitute important evidence," he said.

"Put your emotions to one side."

The court heard earlier from Puhi-Duff's mother Melina​ Puhi, who told the jury how much her daughter loved her father and their daughter would often only settle for Duff. Puhi said she had no concerns leaving their daughter in his care.

The trial is set to continue until the end of next week.

- Stuff