The man who stabbed a Tauranga woman to death believed he had to save himself, his family and his iwi from a "makutu" or curse.

A High Court judge has ruled Tamati Hakaraia Mason was insane when he killed Ariana Mahu during a frenzied attack at Huria Marae.

Tears flowed as whanau and supporters of Mason, and the woman he killed on February 22, filled the public gallery in the High Court at Rotorua yesterday.

The Crown summary of facts revealed that Mason, who is a member of Mahu's extended whanau, and the same Ngati Kahu hapu, was part of a large gathering attending a tangi.


Mahu was helping in the kitchen when Mason, without warning, stabbed her several times in and around her neck with a large knife he got from the kitchen.

Other people tried to intervene, but Mason, still holding the knife, then confronted some of Mahu's helpers, and he was eventually overpowered, disarmed, and held until police arrived.

Despite desperate attempts to save her, Mahu died at the scene.

The attack was witnessed by a large number of mourners at the tangi, the summary said.

Mason told police his killing of Mahu involved a makutu (curse) and he felt relieved about what he had done and was prepared to face the consequences.

He also spoke about Mahu disrespecting him and his family, and showed no signs of remorse.

Mason, whose identity can now be revealed after Justice Graham Lang lifted a suppression order, sat quietly between two Corrections security officers.

Justice Lang said the evidence that Mason was suffering from a significant disease of the mind when he killed Mahu was "compelling".

Both psychiatrists' reports referred to Mason telling them he was hearing voices, and over time they became overwhelming, and he was having delusions, he said.

Mason admitted he intending to stab and kill the victim, and was convinced he needed to do so to "save himself, his whanau and his iwi" from a makutu, he said.

Mason described experiencing "commands from the spirit world" and was acting under Maori cultural customs.

Justice Lang said he agreed with the two psychiatrists that Mason, who had been suffering from schizophrenia for some time, was insane at the time of the killing.

He made an order for Mason to be detained in a mental health hospital as a special patient under the Mental Health (Compulsory Assessment and Treatment) Act.

Two victims read their victim impact statements to the court.

Ariana Eva Mahu, 37, affectionately known as Butterfly, was fatally stabbed at Huria Marae by Tamati Hakaraia Mason. Photo / Supplied
Ariana Eva Mahu, 37, affectionately known as Butterfly, was fatally stabbed at Huria Marae by Tamati Hakaraia Mason. Photo / Supplied

Mahu's eldest son, Te Reihana Pokere, 19, who read his victim impact statement to the court, described his rage when he first found out his mother had been murdered.

Seeing Mahu lying in a "cold, darken grey room" at Tauranga Hospital under a white sheet he immediately felt enraged and wanted to take revenge.

"I feel angry all the time, and I have wanted to go on a violent warpath after you murdered my mum … I'm a very different person today because of what you did Tamati ... You have made my life a living hell," Pokere said.

Karen Whaiapu, a friend and whanau member of Mahu, who also read her statement to the court, said Mahu, known as Butterfly, had touched the lives of countless people.

"Ariana was loved by all. Her beautiful heart, her beautiful smile, her caring and nurturing nature, her love for everyone, and her making everyone feel special.

"She would do things for anyone and everyone. If there was something on, you could guarantee Ariana was there helping ... Ariana was our go-to person for almost everything.

"She accepted everyone as they are and made you feel important, loved, special," she said

Whaiapu said Mahu showed all these attributes towards Mason who she loved and cared for like he was her child and had tried to help him.

"This came out of nowhere, and all of a sudden chaos was everywhere. One minute we were all happy laughing and next minute Ariana was screaming trying to fend you off.

"I can still see Tamati's eyes only focusing on Ariana if no one else existed. Holding the knife, focusing on her with such determination, and that he was going to get her.

"I can still see the smug look on Tamati's face when he put the knife down and casually walked out of the wharekai as if to say ' I got you'," she said.

"Ariana did not deserve what happened. Her sons and whanau didn't deserve this, her friends, our marae, our community didn't deserve what happened," Whaiapu said.

Justice Laing said he knew it had been a "terribly difficult time" for both sides and nothing the court could do to help soften the blow or change what happened.

Outside court, Whaiapu told the Bay of Plenty Times Weekend that there was no sense of relief or feelings that justice had been served by Justice Laing's findings.

"We feel like most of this hearing was all about Tamati and not about us, the true victims."

Whaipau said the outcome had left her and other whanau and friends of Mahu feeling they had been "left in limbo" and there were still lots of unanswered questions.

"Something needs to change for us, the victims," she said.