He took the matter to the Court of Appeal in Wellington earlier this year to argue against the conviction he'd received, but in a decision released today the court declined his bid.
Poihipi claimed to have drunk 18 cans of Cody's before the killing. He then sat next to her inert body for 20 minutes before running to get help from his cousin.
Lynace Parakuka was 22 when her partner violently beat her to death in a Rotorua schoolyard. Photo / Supplied
When they returned to the field Parakuka wasn't breathing, the cousin administered CPR under the direction of a 111 call dispatcher until emergency services took over but after 20 minutes she was declared dead.
Despite his claims of only hitting her four or five times and kicking her in the face once, the pathologist who conducted the autopsy on Parakuka's body uncovered evidence indicating she'd been punched in the head between 11 and 20 times, maybe even more.
His examination revealed she'd died from bleeding to the brain inflicted by blunt force injuries which could have been caused by a piece of wood, a hammer or a hand.
He also found she was in her first trimester of pregnancy.
At the appeal hearing, Poihipi gave evidence by AVL from prison, saying he was high at the time of the killing, having eaten a handful of magic mushrooms and his trial lawyer, Roger Gowing, should have introduced that information to the jury.
But the Court of Appeal disagreed that this omission was relevant, given the evidence around his use of it and the effect on him was inconsistent.
Jayson Wiremu Poihipi appealed his conviction earlier this year. Photo / File
A psychiatrist report also stated research "has not generally found a causal relationship between taking [psychedelic hallucinogens] and violence – indeed the reverse seems to be true … What happened in this case appears to be a rare event".
"In my opinion, Mr Poihipi did know at the time that his actions were wrong for him to perform, and he did mean to attack the victim. He thus does not have a defence of automatism available to him as regards the attack, and he also does not have a defence of insanity available to him," the expert said in his report.
He did say there could have been a "degree of disconnection between mind and body once this attack was underway, in terms of its severity", which the use of mushrooms could have caused.
But the court said even if the jury believed he was having drug-induced delusions, they would have had to believe he did not appreciate his assault was likely to cause death.
Poihipi also appealed on the grounds his lawyer advised him against giving evidence at trial and failed to properly advise him on giving evidence.
The court said there were "clearly disadvantages" to Poihipi giving evidence at trial, and they were satisfied Poihipi had been properly informed by his lawyer.
Poihipi's appeal lawyer, Craig Tuck, said he had "almost every conceivable aspect of vulnerability". He was 19 at the time of the trial, but also had literacy and numeracy issues and mental health problems.
"It was just layer after layer of vulnerability."
But the court found no error with how Gowing handled Poihipi's mental health.
