An Auckland man jointly charged with murder has taken to the witness box to accuse his childhood friend of being solely responsible for killing Wiremu Arapo.

Sean Hayde and Gregory Hart were once close friends and have spent the past fortnight sitting beside each other in the dock during their trial in the High Court at Auckland as the Crown laid out its case.

They are jointly charged with murdering personal trainer Arapo, who was Hayde’s boxing coach and Hart’s flatmate, and burning down the house in Cockle Bay’s Minerva Tce to destroy the evidence.

On Monday, Hayde took the stand in his own defence and set out his version of events, including the moment he alleges Hart slid a knife into Arapo’s neck after a tussle.

Hart will mount a mirror defence when he opens his case, claiming it was Hayde who was solely responsible for the death, his lawyers have told the jury.

Over the past two weeks, the jury has heard the prosecution lay out its case alleging killing was the work of both men.

Crown prosecutor Ned Fletcher said the killing was the result of simmering tensions among the trio. Those tensions boiled over in a bout of extreme violence leaving Arapo dead on October 20, 2020, aged just 27, the prosecution said.

Arapo was in the process of kicking Hart out of the rental they shared after becoming frustrated at the former soldier’s lax attitude towards paying bills, cleaning and life in general, the Crown claimed.

Sean Hayde took to the witness box to give evidence in his murder trial on Monday to say his co-accused Gregory Hart is solely responsible for killing Wiremu Arapo.

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Hayde resented Arapo’s treatment of Hart, according to text messages presented to the jury, and repeatedly discussed meting out violence in revenge. Arapo was once Hayde’s boxing teacher.

“I’m about to turn on the black a***,” Hayde allegedly wrote to Hart on October 17, three days before Arapo died.

“And you should know it’s not good to be on my bad side. Hence move out asap so I can kick his teeth out.”

There were also tensions fuelled by mutual jealousies between Hayde and Arapo over the former man’s new relationship with a friend of the latter.

Hayde’s new relationship had begun as an affair with Arapo’s friend while Hayde was still with a woman he is charged with assaulting, strangling and threatening to kill a few weeks before Arapo’s death.

He also denies these charges and says the woman’s injuries were a result of him defending himself from her, and trying to stop the woman self-harming.

Under cross examination from one of his lawyers, Emma Priest, Hayde described several instances in the lead-up to October 20 where tensions surfaced between himself and Arapo.

As Hayde gave evidence, speaking slowly and with frequent pauses, Hart watched him intently from the dock.

Hayde had once mentioned how he had found his neighbour attractive, he said.

This appeared to have sparked anger from Arapo given Hayde’s blossoming relationship with Arapo’s friend, as shown by a text sent about 24 hours before his death.

“It’s Wiremu. Don’t f*** the neighbour. [Hayde new partner’s] my girl and I don’t want you to hurt her.”

The fire destroyed Wiremu Arapo's wing of the home in Minerva Tce, Cockle Bay

The following day, Hayde and Hart went to Ormiston Police Station. Hart made a statement apparently in support of Hayde relating to the allegations of domestic violence by his former partner.

After this, the pair bought a couple of bottles of wine from Countdown and returned to Hart’s place in Bucklands Beach, where his new partner had made them lunch.

They polished off the two bottles of wine then went out and bought two more, the jury heard.

The afternoon wore on and the pair decided to head down the road to grab yet more drinks, Hayde said.

They were intending to stop by the Minerva Tce home Hart and Arapo shared for Hart to grab something, Hayde claimed.

On arrival at Minerva they realised Hart had left his bank card and keys at Bucklands Beach so they headed back, before returning to the Cockle Bay property, he said.

They arrived at Minerva the second time shortly before 6pm.

Hayde said he followed Hart inside.

Asked by Priest how drunk he and Hart were, Hayde said seven or eight on a scale where 10 denotes “very intoxicated”.

Hayde said he heard yelling and raised voices and went from Hart’s wing of the home to the section used by Arapo.

When he arrived, the scene was tense and it was clear there had been an argument, Hayde said.

Gregory Hart in the dock on the first day of the trial two weeks ago. Photo / Jason Oxenham

Arapo said something about taking Hart’s computer because of the debts he was owed, Hayed claimed.

Tensions again began to climb and Arapo rose from the couch where had been playing PlayStation.

Arapo took a swing at Hayde then missed, he claimed. The men grappled, stumbling around the lounge as Arapo tried to force Hayde to the floor, he alleged.

“I said to Greg ‘get him off me’,” Hayde said.

Hart managed to free Hayde from Arapo’s grip, he said.

Hayde said he then punched Arapo in the face and threw him to the ground, where they again grappled.

Hart repeatedly kicked Arapo to break up the fight, Hayde claimed.

Hayde said he got up as Arapo rolled to his side. He suggested to Hart the pair flee, but Hart had other ideas, Hayde claimed.

Hayde claimed Hart sat on Arapo and began speaking to him.

Both Hart and Arapo had served in the Army. Hayde alleged he told Arapo: “we’re meant to be brothers, we’ve served together”.

“He said a few things like ‘ever since moving in you’ve made my life hell’,” Hayde claimed.

Hayde claimed that at this point, Hart, who was holding a knife, referenced a toast he understood to be used in the military when clinking drinks.

“[He] said it’s meant to be ‘never above you, never below you, always beside you’,” Hayde claimed.

Hart then said “goodbye brother” and stabbed Arapo in the neck, Hayde alleged.

Hayde described pulling the knife from the neck of Arapo, who was still breathing.

Hart wanted to flee but Hayde wanted to stay, Hayde claimed.

At some point, he noticed smoke before realising the house was alight, Hayde told the court.

He was adamant he did not set the fire and said he did not know how the blaze started.

His lawyer Julie-Anne Kincade KC called an expert witness from the UK last week who claimed it could have been started by a candle knocked over during a tussle.

When Hayde was asked why he had not told police initially about the fight that left Arapo dead, he said it was because he was scared about what would happen given he was also involved in the scrap, and that he also wanted to protect Hart.

Hayde and Hart were arrested on December 8 following a police homicide investigation.

He described speaking to Hart as the pair travelled back from the Manukau District Court in a prison van after their first arrest.

He asked Hart if he was all right, who said yes. Hayde alleged Hart then replied “we’ll be going away for a long time”.

“And to that I replied ‘I won’t be’,” Hayde said.

The trial continues.