A 20-year-old man from WA's Great Southern region, who fatally stabbed his older and stronger brother to avoid a beating that could have potentially killed him, has been sentenced to five years' jail.
Sonny Poutu was found guilty of unlawfully killing his 24-year-old brother, Tamahere Tumai, during a drunken argument in the small town of Jerramungup on Easter Saturday last year.
The two had spent the day drinking and Poutu, who was then aged 18, stabbed his older brother in the chest and abdomen during what was described in the Supreme Court as a "face-to-face-style standoff".
Mr Tumai had already assaulted Poutu earlier in the day, leaving him with injuries to his head, bruising and a bloodshot eye and the court heard at the time of the stabbing he believed he was going to beaten again.
On Wednesday, Chief Justice Peter Quinlan said while Poutu honestly believed he was acting in self-defence to stop another assault, his response — to stab his brother twice — was excessive and not reasonable.
The court heard Poutu maintained he picked up the knife because he only wanted to scare his brother but the Chief Justice said instead it escalated the confrontation.
"With the benefit of hindsight it was the worst thing you could have done because once you picked up that knife, he was not going to back down," he told Poutu.
"In all of the violence … and confusion of that day you went too far … further than the law allows."
Rare brain condition taken into account
The Chief Justice accepted one of the mitigating factors in the case was Poutu had a rare brain disease called Moyamoya, which interfered with the blood supply to his brain.
The court heard Poutu had neurosurgery in 2016 to improve the blood supply, but afterwards he and his family were warned any forceful contact to his head could put him at risk of suffering a potentially fatal stroke.
Despite that, the court heard Mr Tumai had assaulted his younger brother on at least two previous occasions, as well as on the day of the stabbing.
The Chief Justice said while the disease may not have been at the forefront of Poutu's mind at the time, it was something that was always with him, and made him vulnerable.
The court was told immediately after killing his brother, Poutu collapsed over him and began crying uncontrollably while saying "sorry."
The Chief Justice said he was satisfied Poutu's remorse from that moment was genuine and he had suffered considerable shame and regret for taking the life of his "precious brother" whom he, and others, loved.
Chief Justice Quinlan also said reports indicated Poutu had generally good prospects for the future and he had the support of his family.
"Your family love you and they want the best for you," Justice Quinlan said.
"The best way now you can try to make it up to them, is to live the best life possible you can and make the most of yourself."
Poutu will have to serve three years before he can be released.
The sentence was backdated to the time of his arrest in April last year and with time already served, he will first be eligible for release in April 2022, although the court heard he may then be deported to New Zealand where he was born.
