David Benbow found guilty of murdering childhood friend Michael McGrath

Christchurch man David Benbow has been found guilty of murdering his childhood friend, a High Court jury has found.

Michael McGrath was last seen at his Halswell home in May 2017.

The body of the 49-year-old Christchurch builder has never been found.

Long-time friend and former corrections officer, Benbow was charged with his murder two years later, in 2019.

The 54-year-old was accused of fatally shooting McGrath with his own gun.

But that firearm has also never been found.

The jury of six women and six men reached their verdict after three days of deliberating at the High Court in Christchurch.

The seven-week trial was Benbow's second, with the first jury being unable to reach a decision on the case earlier this year.

Crown prosecutors argued Benbow was the only person with the "motive, the means, and the opportunity" to kill McGrath.

Benbow was devastated after learning through his daughter that McGrath was seeing his ex-partner of 17 years, Crown lawyer Claire Boshier said.

"'I would like to annihilate him' - those are the words used by the defendant in this trial, Mr David Benbow, about the deceased in this trial Michael McGrath, 20 days before Mr McGrath disappeared," she said.

"'I don't give a f*** what happened to him, it just teaches you not to introduce your partner to another man.' That is what Mr Benbow said about Mr McGrath after his disappearance."

The defence said Benbow did not know what had happened to McGrath, and police hadn't looked hard enough at alternative explanations.

His missing gun was key to the case.

In his summing up, Justice Jonathon Eaton said the Crown saw only one explanation: Benbow had deliberately got rid of it.

"The Crown asked could it be just a most unfortunate coincidence that a man being investigated as a suspect in the disappearance of a friend, who is now in a relationship with his ex-partner, can't explain where his 22 firearm and ammunition are," Eaton said.

But the defence argued Benbow would have to know where the gun was if that theory was true.

"If the Crown are right and Mr Benbow had carefully planned this murder that he had used his own firearm but had no sensible explanation for being unable to account for it," Eaton said.

The Crown also questioned why Benbow went to the dump a day after McGrath's alleged death and had not proactively told the police about it.

The defence's view was that it was "just somebody getting rid of old clothes and rubbish collected. It was innocuous and it's no coincidence, the defence say, that not withstanding all those hours of searching at Kate Valley landfill nothing was found, because there was nothing to be found, because they were targeting the wrong person," Justice Eaton said in summing up.

Police had searched the dump for 8000 hours.

In a statement on Thursday after the verdict was delivered, Detective Inspector Kylie Schaare thanked McGrath's family and those close to him for their "much dignity and grace through what has been the worst time of their lives".

"They have had to endure the stress of a long investigation, two trials and having their loved one and their own lives laid bare in a court room," Schaare said.

"We knew that no outcome today could make up for the grief and loss they have endured, as nothing brings Michael back," she said.

"My one hope is that they can now move forward in starting to process their grief and the loss of their son, brother, partner, and friend."

She also thanked the investigation team for working "tirelessly during the past six years to find answers for Michael's loved ones".

"This investigation has been a massive undertaking and I give particular thanks to the police trial team and the Crown Solicitors, who have spent many weeks away from their own families during the investigation and this trial and have been so committed and professional throughout."

Schaare said her one wish was that McGrath could be returned to his family.

McGrath 'sorely missed', family elated with verdict

McGrath's family spoke outside the courtroom, saying they were elated by the jury's verdict. They had clapped and cheered as it was read out moments earlier.

Spokesperson Simon McGrath, Michael McGarth's brother, said there was no doubt in their minds Benbow was guilty.

"It's been just over six years since Michael went missing and today's guilty verdict is welcomed by the McGrath family and friends of Michael," he said.

"It is without doubt a hugely bittersweet moment. Michael was a meticulous and talented builder who was hugely loyal, humble and unassuming. He's sorely missed.

"Michael has been taken away from us in the most cowardly, pre-meditated and murderous manner. The horrific, nature, legacy and trauma will haunt the family for the rest of our lives," Simon McGrath said.

The feeling he had in court today was like nothing else he had ever experienced, he said.

"It's a just verdict. There's absolutely no doubt in our minds that this is a just verdict."

But the previous trial's hung jury cast a shadow over the courtroom, McGrath said.

"It had to be a concern, it was a circumstantial case. I was always a bit concerned that we wouldn't get it over the line.

"It was hugely emotional ... We'd like to thank NZ Police for their professionalism, ongoing commitment and tenacity during this massive investigation. They exemplified a master class in circumstantial information gathering," he said.

The family also thanked the Crown prosecutors and court staff involved in the case.

And if given the chance to speak face-to-face with Benbow, McGrath said he had one question for him: "Where is Michael?"

The trial took seven weeks, and heard testimonies from more than 100 witnesses.

Benbow will be sentenced on 5 March, 2024.