No one knows exactly how a 10-month-old Rotorua baby died a violent death, but the man responsible for inflicting the fatal injuries will spend six years and five months behind bars for killing him.
Shane Claude Roberts, 61, appeared in the High Court at Rotorua today for sentencing after being found guilty last year by a jury of Karlos Stephens' manslaughter. The jury found Roberts not guilty of the baby's murder.
To this day, Roberts denies he did anything to Karlos overnight on November 29, 2014. Justice Sarah Katz said based on the evidence, the most likely scenario was Roberts woke in the middle of the night to tend to Karlos, who was suffering from flu-like symptoms.
In a moment of frustration in dealing with the sick and irritable child, Roberts threw the baby either against a wall or on the floor, Justice Katz said.
Karlos later died in hospital from a severe brain injury.
It was the defence's case that Karlos' mother, Pamela Stephens, had likely caused the fatal injuries - a suggestion which Justice Katz said the jury understandably rejected.
Stephens gave birth to the twins in January 2014 when she was already a single mother to four other sons.
Struggling to cope, she took up an offer from Roberts to care for her twin sons, despite only meeting him a few weeks earlier.
Stephens agreed Roberts could care for her twins given he would be helped by his ex-partner, Rachel Broughton, who had together with Roberts already raised twin daughters.
Much of the day-to-day care of the twins fell in the hands of Broughton and her twin daughters, although Roberts had significant involvement and clearly loved Karlos and his twin brother, Justice Katz said.
When Broughton and her daughters had to travel to Christchurch for a family graduation, Roberts was left in the sole care of the twin boys for a week.
Roberts decided to look after the twins at his ex-partner's house on Homedale St as there was no power at his Allison St property.
He arranged with Stephens to stay at his Allison St house so she could spend some time with her boys.
Roberts left the boys with Stephens for a short period of time on the day of November 29, 2014, before taking them to his ex-partner's home on Homedale St. The fatal injuries happened overnight.
About 7.30am on November 30, Roberts was seen leaving the Homedale St house in a panic with the twins. Justice Katz said Roberts was in so much of a rush, he didn't put the twins in proper car seats and left the doors to the home wide open.
He went to see Stephens at Allison St and told her Karlos was not breathing. He then drove baby Karlos to the hospital at the request of Stephens.
Justice Katz said Roberts concocted a story Karlos had been at the Allison St home and as a result a police scene examination was carried out there, and not at Homedale St.
She said given the rush in which he left the Homedale property with the babies, it was likely he didn't realise Karlos had been gravely ill overnight.
"It was the middle of the night, you were no doubt tired and it is possible you didn't realise the seriousness of the situation."
Justice Katz said Karlos' birth family would always be haunted by the fact Roberts had not taken responsibility for his death.
A cultural report showed Roberts had been brought up among abuse, anger, drinking and violence that was "unforgiving, raw and savage". As a child, he suffered beatings that had potentially resulted in mild brain injuries.
Roberts found solace in the Mongrel Mob and spent two decades with the gang before leaving to concentrate on being a better father to his eight children.
Justice Katz said despite his violent upbringing, there were no relevant violence convictions in his history.
Before the sentence was handed down, Karlos' grandmother read a victim impact statement to the court through tears.
She described Roberts as a "manipulative liar" who only cared about himself.
She said her daughter had her issues but she was always involved with her children and Stephens and her children would from time to time live with her.
She said it was her understanding Roberts was only caring for the twins temporarily.
"He has not let me or my family have a say in what was happening."
She said he made the family believe Karlos died from cot death or meningitis.
She said it was hurtful to hear during the trial Roberts was trying to make out her daughter was violent and could somehow be responsible for Karlos' death.
"I want (Roberts) to know he is a monster. We will never have closure while Karlos is buried in the middle of nowhere."