Turipa-Wano was "overwhelmingly remorseful" she said, and Corrections officers had described him as being in emotional turmoil with a need to be closely monitored while in jail.
The incident happened when Mr Mita, Turipa-Wano and others were partying. Witnesses said Turipa-Wano was a respectable member of society when not intoxicated or under the influence of drugs, but he became aggressive and intimidating at the party after consuming alcohol, cannabis and methamphetamine.
He threw bottles at a wall, flipped a table and armed himself with a knife and a wrench.
He smashed holes in the wall with the wrench and had told party-goers: "I will f****** kill someone. I may be slow, that's why I use weapons."
The stabbing happened as others tried to restrain him. A man who tried to persuade Turipa-Wano to calm down suffered a 10cm wound on his forearm and was now permanently scarred. Mr Mita tried to disarm Turipa-Wano but was stabbed twice in the chest under his left lung.
Police arrived and found Turipa-Wano in his parents' home, where he had smashed his way into a cupboard to get his father's gun. He could not find the bolt but pointed the weapon at a police officer before surrendering as he was told Mr Mita had died.
Turipa-Wano was also convicted of wounding the other injured man with reckless disregard for the safety of others and unlawful possession of a firearm.