Newcastle Supreme Court Justice Natalie Adams on Thursday said she was unable to say if Tyler King had intended to kill Jesse Tattersall and was sentencing him on the basis he wanted to cause Tattersall grievous bodily harm in the hope he would never hurt his sister again.
After stabbing Tattersall twice, King told his sister, "No one's going to f***n' hit you again, no one's going to hurt you again" before stabbing Tattersall a third time.
King, 27, of Budgewoi, pleaded guilty to the manslaughter of Tattersall, 33, at Hamlyn Terrace on September 8, 2022.
Justice Adams said King claimed, from his perspective, his sister Tenille was being violently attacked by Tattersall and he had to do something.
"Tenille had told him she was scared of the deceased and asked him to come to the house to protect her," the judge said when jailing King for six years and nine months with a minimum of four years and three months.
"After that, the deceased had smashed his way into her property through a security door and immediately begun to violently assault her. She was defenceless against this attack."
When King confronted Tattersall just after 8.10pm as he was dragging his sister through the living room, Tattersall said, "Sorry bro, sorry bro. I won't hit her again."
Tattersall, a father of two, then slammed King's head through a plasterboard wall before telling him, "You should see what I do to her in the bedroom".
King, who had been on bail for aggravated burglary, grabbed a knife from the kitchen as the pair fought and he stabbed Tattersall three times while Tenille tried to separate them.
Tattersall, who earlier in the night threatened to kill Tenille after an argument, stumbled out of the house, and collapsed and died outside a neighbour's home.
Justice Adams said it was clear Tattersall intended to assault Tenille and she accepted, to some degree, King had acted out of fear and panic.
"At the time of the assault by the deceased on Tenille, the deceased no doubt thought she was alone in her home and he could assault her freely. There was no evidence, when he commenced his physical assault on her, he knew Mr King was present.
"It is a feature of domestic violence offences that they often occur at home with no witnesses."
The judge noted King had been a talented speedway racer from a loving family who left school and travelled to the United Kingdom to compete professionally at the age of 15 on a one-year contract but didn't have the success he expected.
He returned to Australia, never went back to school and his life spiralled out of control when he became addicted to drugs.
After stabbing Tattersall, King's then girlfriend, Maddison York, 21, called an Uber and the pair fled the scene before being arrested at Gorokan.
York, who pleaded guilty to being an accessory after the fact to the killing, was convicted on Thursday but allowed to walk free after spending 19 months in prison following her arrest.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
12°C