Warning: Distressing content

The devastated parents of a Tairua man who was rammed off the road and shot three times on an isolated highway say their world has stood still since he was murdered.

Bayden Williams was driving along the Kopu-Hikuwai Rd on the night of August 5, 2020 heading to meet his ex-girlfriend Chloe Randall and their baby son for dinner.

Harbouring a malicious grudge, Adrian Reginald George Phillips knew of Williams' plan and was waiting for him, before crashing into him, sending his prized Jaguar down a cliff.

Phillips - who was Tuesday jailed for 14 years for murder - then shot Williams three times with a shotgun.

Phillips, from Ngatea, claimed he shot 20-year-old Williams in self-defence as Williams lunged at him.

But the Crown said Phillips was an angry, aggressive man who harboured a grudge against his former friend after Williams got the upper hand against him in a fight eight months earlier.

After a five-week trial in the High Court at Hamilton, a jury deliberated for three hours, returning with a unanimous guilty verdict on July 1.

Phillips was back in court this morning for sentencing before Justice Melanie Harland and a packed public gallery of his own family but also family and supporters of Williams.

Williams' father, Lance, told the court that his world has stood still since the day his son died.

"Adrian, it's been nearly two years since the day that you shot and killed our son but it feels like yesterday as our world has stood still.

"Bayden was run off the road by you ... and shot by you not once, not twice but you reloaded a third time for the fatal kill shot to the face then rolled him into the bush like an animal.

Adrian Phillips. Photo / Supplied

"No father should have to be called to a morgue to identify his son in a body bag with one side of his face blown off by you.

"It's an image that will remain with me forever.

"You not only put hundreds of holes in our son, you put holes in the hearts of everyone who loved Bayden."

Williams' mother, Tracey, spoke of her heartbreak since her firstborn was shot dead.

"Bayden was such a huge spark of life in our lives and you snubbed him out.

"Adrian, you have truly ruined our lives," she told the court.

Phillips was in a relationship with Chloe's twin sister Macy Randall and was unhappy about the prospect of Chloe and Williams rekindling their relationship.

He wanted an apology from Williams who put him in a headlock and held him down while Macy and Chloe's father Peter Randall fought with Lance Williams on January 11, 2020.

The Crown contended Phillips felt "embarrassed, humiliated and emasculated" afterward and made a number of threats of violence against Williams on social media to friends, including the day before he shot him.

By early 2020, Phillips had a short fuse, was triggered to anger easily, and was having daily rages, including at Macy.

Phillips illegally bought the sawn-off shotgun and ammunition in the weeks before the shooting.

Crown prosecutor Jacinda Hamilton said Phillips' actions were "a retributive attack .. in circumstances where [Phillips] considered Bayden had wronged him".

"There was evidence that he had driven a deep-seated grudge and spoke of a number of occasions to cause him physical harm.

"This was an ambush at the time the defendant approached Bayden Williams in his vehicle."

She said it was unlikely Williams would have known who was running him off the road or appreciated the extent of the anger Phillips harboured toward him.

Hamilton also urged Justice Harland not to put too much weight on Phillips' mental health defence.

"I say it's very clear this offending ... s not the result of a mental illness.

"It's the result of the actions of an angry and vengeful man."

She pushed for an end prison sentence of between 15 and 15 and a half years, while Phillips' counsel Ron Mansfield urged the 10-year minimum non-parole period for the murder charge.

He argued that without an understanding of his client's flailing mental health it was "hard to understand how this offending occurred at all given all we know of Mr Phillips prior to a fire in 2018".

That fire, around Christmas time, saw Phillips seriously burned at his home after pouring alcohol on a bonfire.

"That fire was a traumatic and significant, defining moment in Mr Phillips' life, sadly."

Mansfield said people shouldn't fool themselves into accepting his emotional injuries were identified let alone treated in the lead-up to the shooting.

He fired a shot at the state of the country's mental health system, saying "we pay lip service to the dire need in our community".

"Why are we so slow to recognise our mental health needs. It seems absolutely clear that Mr Phillips would not stand where he is today for murder but for his mental health which was left untreated."

That in turn changed Phillips from a "caring and gentle young man into a killer".

Justice Harland said being run off the road must "have been terrifying for Mr Williams".

Having already shot Williams twice, he was no threat, she said.

"You believed there was a knife. No knife was ever found.

"It was during Mr Williams' last attempt to get up the bank that you fatally shot Mr Williams when he was less than a metre from you.

"The jury rejected your defence of self-defence and so do I."

Justice Harland accepted he didn't set out to kill Phillips that night, but was armed with an "inherently dangerous weapon".

She also accepted that prior to the 2018 fire, he was of good character, a "hard worker and well-liked".

She also read part of Phillips' remorse letter to the court in which he detailed how he would "never forgive myself for what I did".

"If I hadn't gone to confront him that night he would still be here."

Phillips earlier pleaded guilty to a charge of unlawful possession of the shotgun and was also sentenced for that Tuesday, a charge she found to be "significant".

- Belinda Feek, Open Justice