Breingan sobbed as he was acquitted in June of a serious drugs charge relating to the production of a substance used to make methamphetamine.

Both he and Mercer denied knowledge of the alleged lab, which contained equipment the Crown said had been used in the manufacture of methamphetamine and was uncovered in steep, dense bush down the back of their McLaren Falls property, outside Tauranga.

The jury was hung on six other charges the man faced. The most serious – that of manufacturing methamphetamine – had already been dismissed by the judge, as had Mercer’s charges at the end of the Crown evidence.

On Thursday morning, in Tauranga District Court, it was confirmed the Crown would not seek a retrial for the charges for which the jury had been hung.

Lisa Mercer, Mark Breingan's partner, also faced drugs charges, but they were dropped at the conclusion of the Crown evidence. She had earlier pleaded guilty to possession of cannabis, which she said was for medicinal use. Photo / supplied. 

But while Breingan was facing the drugs trial, he was also awaiting sentencing for manslaughter. That link couldn’t be reported until suppression was lifted this week.

Excessive self-defence following gang attack

Breingan was sentenced by Justice Tracey Walker at the High Court at Rotorua in June, having been found guilty of manslaughter after a trial earlier this year. That came after an earlier trial that resulted in a hung jury.

At sentencing, the court heard Breingan thought he was in for another beating, having suffered a violent gang-related attack that morning during which he had been impaled through his shoulder with a steel rod.

So when he saw Jamin Roemaata Harrison on his CCTV, standing at the gate at his rural property near Tauranga, Breingan came out of his house with a shotgun and fired down a treeline, hitting the 30-year-old in the chest and abdomen.

Harrison died at the scene.

Breingan was sentenced to three years and nine months’ imprisonment.

Harrison’s family members, who attended the sentencing, spoke of him as a loving father to his two children, and a man who had a “heart of gold”.

‘Only by chance you weren’t killed’

Justice Walker said Breingan had been suffering from a form of PTSD when Harrison arrived at his house.

Both he and Mercer had suffered a vicious attack by Rebels gang members earlier that day.

Justice Walker addressed Breingan directly telling him it was “only by chance you were not killed that morning”.

After the violent assault, police had attended but she said he had refused offers of help, thinking police involvement would “make matters worse”.

“You made statements to the police along the lines of, ‘you would be sorting it yourself through your own channels’”.

The judge said this didn’t mean he’d necessarily intended “vigilante action”, but it seemed he’d had no confidence in the police’s ability to protect him at his semi-rural property.

When Breingan and Mercer saw Harrison on the CCTV camera, they recognised him as someone associated with the Rebels leader who they knew had orchestrated the attack on them earlier that day.

The judge said Harrison had been a “pawn of the individual behind the scenes”, and there was no evidence to suggest Harrison had known about the earlier assault.

Mercer, who was “terrified”, had either been mistaken, or had misspoken, when she told him she could see Harrison had a gun.

He responded by going outside and turning on floodlights before he fired down the tree line towards Harrison, who was about 23 metres away.

Breingan’s defence at trial was that he’d fired the “warning shot” in self-defence, believing the gang members were back to “finish [him] off”.

When the man and his partner realised someone had been shot, they ran and called an ambulance and followed instructions for CPR.

They then ran off when they saw a car turn into their driveway, believing that more gang members may have arrived, but went to a neighbour’s house to wait for police to arrive.

The judge began with a starting point of six years and three months’ imprisonment, which she said took into account the jury’s conclusion that he’d exercised “excessive self-defence” when Breingan mistakenly believed he was under attack.

Discounts were then given for mitigating factors, which included the man’s offer of a guilty plea for manslaughter, but which the Crown chose not to accept, proceeding to two murder trials instead.

The judge said the offer of the guilty plea for manslaughter was “vindicated” by the jury, and he was entitled to a 15% deduction.

She said the most important mitigating factor was the “acute stress disorder” that resulted from the traumatic events on the morning of the offending.

That had the “single most causative impact” on the offending, Justice Walker said.

His instinctual reaction had a “disordering effect” – his judgment and actions had been impaired by his PTSD.

He had prospects of rehabilitation but only if he “steers clear of the kind of people who in the background to this offending, orchestrated your assault”.

Considering these factors he was given a deduction of 20%.

He was also given a further 5% deduction for remorse, with several reports provided to the court indicating the man’s feelings about the incident.

“He has a family, he’s someone’s son, and I did that,” Breingan said.

He told a report writer he had never meant to kill anyone, he’d just wanted the perceived threat to go away.

He’d offered to take part in restorative justice if that would help Harrison’s family.

The judge reached an end sentence of three years, nine months’ imprisonment.

Hannah Bartlett is a Tauranga-based Open Justice reporter at NZME. She previously covered court and local government for the Nelson Mail, and before that was a radio reporter at Newstalk ZB.