The de-facto stepfather of Christchurch infant Ihaka Stokes has today been jailed for life with a minimum non-parole period of 17 years for bashing the boy to death in his cot in what has been described as a "momentary loss of temper".

Troy Kevin Taylor, 24, had denied murdering the 14-month-old boy during a two-week trial at the High Court in Christchurch earlier this year.

He claimed that his then-partner and Ihaka's mother Mikala Stokes inflicted the boy's 59 fatal injuries on July 3, 2015 while he was out getting a tattoo.

But after four hours of deliberations, a jury of six women and six men were unanimous in finding Taylor guilty of murder.

They also found him guilty of assaulting the child the day before the murder.

The Crown had alleged that Taylor was suffering from sleep deprivation, headaches, and irritability caused by multiple concussions around the time Ihaka was developing an ear infection, when he "snapped".

The public gallery was packed for Taylor's sentencing today.

In an emotional victim impact statement, Mikala Stokes said she lost her two best friends over that fortnight nearly two years ago and has been left "broken".

In the hospital, Stokes never got the chance to say her final goodbyes to her son.

She felt like he was being "treated like a science experiment".

Being pregnant got her through, she said today, but has been left with high anxiety and struggles to trust anyone.
She said to Ihaka she was "sorry".

Ihaka's grandfather, Mikala's father Paul Stokes, said Taylor had been a "doting father figure and mate" to Ihaka.

He's found the legal and medical process frustrating and overwhelming. It's taken a toll on his family, put a strain on his marriage, and he now struggles to get out of bed every day.

Ihaka loved rainbows, and after his death Stokes carved him a rainbow, which its at the entrance to the family home, and says, 'If tears were stairs, I would build a staircase to heaven and bring you home'.

Crown prosecutor Mark Zarifeh accepted it was a case of "momentary loss of temper".

"That unfortunately is the case in a lot of these kinds of killings," he said.

Defence counsel Phil Shamy said Taylor clearly maintains his innocence.

But he said it would have amounted to a "momentary loss of control", and that it was offending "completely out of character".

The court earlier heard how Taylor told police just minutes after the boy's death at the couple's Truman Rd home how he heard two "bangs" in the night and thought he'd fallen in his cot.

Giving evidence, Taylor said he lied to police about the fall to protect the heavily-pregnant Stokes.

He testified to say that Ihaka was floppy and breathing raspily when he got into the child's cot earlier in the evening.

Worried that Stokes had done something, he baulked at getting medical help because he didn't want to get her into trouble.

He claimed he would've "gone to prison" for her if she'd admitted hurting Ihaka in a four-hour window that he was out of the house.

But Zarifeh said in his closing address that the medical evidence heard in the trial - which Taylor dismissed, saying "science gets lots of things wrong" - completely undid his story.

UK neuropathologist Professor Colin Smith believed it was a "maximum of minutes" from the time Ihaka received his injuries before he became unconscious.

Asked to comment on defence suggestions that Stokes inflicted the injuries in the afternoon - at least three hours before Taylor says he found him unresponsive in his cot - Smith replied: "That is not an explanation for the pathology that is present in this case."

Zarifeh said the medical evidence was not consistent with Taylor's account, and also independently showed that Stokes couldn't have inflicted the injuries on the Friday afternoon.

Taylor lied to police that fateful night, Zarifeh said, not to protect Stokes, "but to protect himself".

Ihaka died in hospital from what is agreed was non-accidental, violent injuries, including broken bones and severe brain damage.

Justice Cameron Mander said children have a right to be safe in their own homes.

It was understandable that the jury did not accept Taylor's version of events, the judge said.

"The evidence was simply irreconcilable with your denial," Justice Mander said.

It is likely, the judge said, that Taylor "snapped" after becoming frustrated at being unable to settle Ihaka and the violence inflicted was "the result of your sudden rage".

While the judge accepted Taylor's sorrow at the boy's death as being genuine, his attempts to cover-up his crimes demonstrated a "certain callousness" and disregard for Ihaka's family. It also showed an inability for him to "face up to the enormity of your actions".

In sentencing Taylor to life imprisonment, Justice Mander did not find a minimum non-parole period of 17 years to be manifestly unjust.