A knife-obsessed teenager who stabbed an 18-year-old in a jealous rage at a birthday party has been sentenced to a minimum of 11 years jail and ordered to undergo counselling.
Theodore Derrick-Hardie, 18, admitted murdering Warren Rosillo at a party on July 29, 2011 on the first day of his trial at the Auckland High Court in July this year.
Today, he was sentenced to life in prison with a minimum non-parole period of 11 years.
He was also told to seek help for conflict resolution, dealing with rejection and violence.
Rosillo's mother spoke tearfully on behalf of her husband today, but details of their victim impact statement were suppressed by Justice Edwin Wylie.
Members of both families sat quietly in the public gallery, some sobbing throughout the sentencing.
The killing was described as "callous" and premeditated by Crown prosecutor Shaun Cathcart.
He referred to a "striking similarity" between Derrick-Hardie's comments on Facebook five months prior, and his actions on the night he killed Rosillo.
Derrick-Hardie had been obsessed with knives in the months before he murdered Rosillo.
A court heard at Derrick-Hardie's murder trial that a month before the killing he and his girlfriend, whose name is suppressed, went to meet his ex-girlfriend and her new boyfriend, who they had been exchanging abusive text messages with.
Derrick-Hardie armed himself with a machete and gave the girlfriend a pocket knife, but the meeting never happened.
On July 21, 2011 Derrick-Hardie bought a 19cm Lebendwell folding knife from King of Knives.
His girlfriend broke up with him the next day after she found photos of the accused's ex-girlfriend on his computer.
During a fight they had, he said the break-up was all his ex's fault, and he would "find her and slice her throat".
On July 29, Derrick-Hardie went to a friend's birthday party in Pakuranga.
Rosillo, who did not know Derrick-Hardie, was also there, as was his now ex-girlfriend.
At about 10.30pm, Rosillo and the girl were flirting and talking. Derrick-Hardie asked her to go outside with him and they began fighting.
Rosillo tried to defuse the situation, but when Derrick-Hardie accused the girl of being unfaithful to him she got angry and kissed Rosillo.
Derrick-Hardie grabbed him around the back of the neck, pulled him closer, whipped a knife out of his trouser pocket and stabbed Rosillo several times in the head, chest and abdomen.
Rosillo staggered onto the road while his friends unsuccessfully tried to save his life.
Derrick-Hardie fled the scene and was found at a room at the Heritage Hotel the following night.