Witness heard baby whimper

Patricia Pickering (above) is charged with murdering 3-year-old Dylan Hohepa Tonga Rimoni. Photo / Paul Estcourt

Patricia Pickering's neighbours heard a woman "screaming in anger", whimpering from a small child and thumping noises coming from her Papakura home hours before her adopted son was rushed to hospital with critical head injuries.

Pickering, 38, called emergency services at 12.20am on April 16, 2008, to say 3-year-old Dylan Hohepa Tonga Rimoni was unresponsive and struggling to breathe.

He was rushed to Middlemore Hospital but died two days later when his life support was switched off.

An autopsy revealed he died from massive head trauma that caused his brain to bleed and swell so badly it was squeezed down into his brain stem.

He was also found to have an older brain injury and a healing rib that had been broken sometime during the three months before he died.

The Crown alleges a frustrated Pickering slammed Dylan's head against an "unforgiving" surface - such as a door, wall or the floor - on April 15.

She has pleaded not guilty to murder, two counts of causing him grievous bodily harm and one of assault and yesterday went on trial in the High Court at Auckland.

Opening the Crown case, prosecutor Phil Hamlin said Pickering was the only person at home the day the injuries were inflicted.

He said she must have intended to kill him when she slammed him against the hard surface or known death was a possibility.

Hours before she dialled 111 concerned neighbours heard yelling from her house and came out of their homes to see what what was going on.

"They heard a woman screaming in anger, a small child crying or whimpering, sounds of thumping ... And then quiet."

Mr Hamlin said Pickering had been playing internet poker throughout the day and was the only other person at the address the day the Crown says Dylan was injured.

At first she told police he'd hit his head falling from the trampoline but later admitted that wasn't true.

After Dylan's death police examined Pickering's home and found a hair from his head in an indentation where the door had been pushed in.

A blood stain from Dylan was also found on a wall and there was "obvious damage", including holes in the walls, that the owner said hadn't been there during an earlier inspection.

An analysis of Dylan's hairs showed he'd had exposure to methamphetamine.

"It doesn't mean he's had it but he's been exposed to it or absorbed it," Mr Hamlin said.

The court heard Pickering's partner had admitted owning items used to manufacture methamphetamine that were found in the house.

Frank Hogan, representing Pickering, said there was an "absolute denial of any offending whatsoever by the accused".

In relation to the murder charge Mr Hogan said the timing of Dylan's injuries was of "crucial importance".

The Crown medical evidence was "fundamentally wrong" when it said Dylan had to have been fatally injured on April 15, he said.

There would also be a "complete denial" of the neighbours' account of what they heard the night of April 15.

The trial has been set down for four weeks.