Manurewa baby death: Murder trial begins for Anthony Pickering, accused of killing son

Police guard the scene at a house on William Ave, Manurewa, where 10-month-old Poseidyn Pickering died in September 2020. Photo / Dean Purcell

Ten-month-old Poseidyn Hemopo-Pickering received "catastrophic head injuries" at his South Auckland home on the day before he died, prosecutors said today as the murder trial began for his father.

Anthony Simon Pickering, a 32-year-old landscape gardener, briefly pulled down his mask as he told jurors in the High Court of Auckland that he is not guilty of the charge.

But his explanation to police of what happened to his son on the afternoon of September 5, 2020, is "complete and utter nonsense", Crown prosecutor Todd Simmonds told jurors today during his opening address, describing the defendant as having "violently assaulted" his son.

Emergency responders were called to the child's Manurewa home that same evening to find baby Poseidyn not breathing and with a grey pallor.

"He had no pulse and he was found to be in a deeply unconscious or comatose state," Simmonds said, explaining that first responders took urgent steps to resuscitate him - rushing him first to Middlemore Hospital, then Starship hospital.

Anthony Pickering spoke to police three times that evening and the following day.

During the third interview, which was recorded and expected to be played for jurors later in the trial, the defendant said he had been alone with Poseidyn and the child's 2-year-old sister that afternoon in a bedroom they all shared.

"He said that while he was sitting or lying on the bed ... the two children ... had, to use the words of Mr Pickering, a bit of a scuffle on the bed," Simmonds explained, adding that the father told police he heard "a bit of a donk noise".

The defendant said his son "had a little cry at that stage before he quickly settled down and he dozed off to sleep in that bed".

"The Crown makes it clear to you now that explanation is not a plausible explanation for the injuries inflicted on Poseidyn," Simmonds said.

He warned jurors they will have to evaluate some "fairly confronting" evidence.

A child's car seat sits the Manurewa driveway where 10-month-old Poseidyn Pickering was injured in 2020. Photo / NZME

"It's vital we have that material before you," he said.

Twelve people were living at the William Ave address in Manurewa on the day of the injury, including six adults and six children, authorities said. Jurors were shown a flow chart of the occupants, including the defendant, his partner and their two children.

Poseidyn, who wasn't yet walking and spent much of his time on his mother's hip, was responsive and playing on the floor that day as his mother made lunch, authorities said.

After lunch, the mother put him down for a nap in the same room as the defendant and left the house with her sister to get some cooking oil from a friend's house. CCTV footage shows they left at 2.52pm and returned about 17 minutes later, at which point the children's mum told police she went straight to the family's bedroom.

Poseidyn appeared to still be napping but in a different position than she left him, she would later tell police. She recalled kissing her son on the cheek when the defendant told her, "Don't do that. You'll wake him up."

The tired young mother then took a nap for 60 to 90 minutes, until she was woken up by the defendant, Simmonds told jurors.

"He was holding Poseidyn in his arms and he said to her, 'Ring the ambulance,'" Simmonds said. "She immediately noticed that Poseidyn did not appear to be okay.

"She could see the whites of his eyes. He appeared to be struggling to breathe."

She grabbed him, screamed for her sister and they called for an ambulance at 4.59pm.

Paramedics arrived less than 10 minutes later and administered CPR, managing to get a pulse. Upon arrival at Middlemore Hospital, a doctor immediately noticed a soft spot on the back of the baby's head and decided to alert police.

During discussions with police, Pickering said he had been either watching TV or playing a videogame and didn't have his eye on his children when he heard the "donk" and realised Poseidyn had hit his head on the window sill. He said it slipped his mind to mention the incident to his partner when she returned home, according to prosecutors.

"I didn't do anything to Poseidyn," police recorded him saying. "I didn't touch him."

When asked how the injuries could have occurred, the defendant said he didn't have a clue before suggesting it could have been an accumulation of injuries resulting from rough play with the boy's 2-year-old sister.

But two family members who confronted Pickering at the child's tangi a week later are expected to testify that the defendant gave a different explanation to them.

"Mr Pickering told them that he had in fact struck Poseidyn, causing him to hit his head on the window sill," Simmonds said, adding that the defendant suspected his nephew was the child's actual father and that had made him mad.

He and the child's mother had argued about paternity two days prior to the child's injuries, prosecutors said.

Justice Michael Robinson kept jurors at the courthouse late this evening but sent them home partway through Simmonds' opening address. The prosecutor is expected to finish his address tomorrow, followed by a short opening statement from defence lawyer Quentin Duff.