A man who strangled a greengrocer for allegedly sexually harassing his mother has been sentenced to a maximum of 28 years in prison for his role as "executioner".
Mathew Aquilina, along with David Comber and Karen Dawson, was convicted of murdering Adrian Trevett in an old butter factory at Red Range in northern NSW in October 2010.
The trio attacked the 62-year-old after Aquilina's mother Dawson alleged he had sexually harassed her and had seen him touching a child inappropriately.
Over the course of several hours Mr Trevett was struck with an iron bar, punched and tormented.
In sentencing Aquilina for his role in the murder, Justice Geoffrey Bellew said the 27-year-old had been the primary strangler - putting a noose around the greengrocer's neck and pulling on it for somewhere between 15 to 20 minutes.
"One can only imagine the anguish and the helplessness which would have been experienced by the deceased in the final moments of his life," he said at the Supreme Court in Newcastle on Friday.
"He lay on the ground, gargling and gasping for air."
After killing him they dumped his body in bushland.
Justice Bellew found Aquilina had "ambushed" Mr Trevett and motivated by vengeance, acted as "an executioner".
This was done, he said, despite Aquilina expressing doubts about his mother's allegations.
He found Aquilina, who had a history of depression and alcohol and drug abuse, had profited from the crime by then selling the bicycle of Mr Trevett, who sold fruit and vegetables from a cart in Glen Innes.
The court heard Aquilina had also shown no remorse, writing in a letter to his mother while in custody: "It was all worth it to me because of what that old dirty c***'s done".
In December last year Dawson was sentenced to a maximum 23 years in prison while Comber received a maximum of 23 years and four months.
Aquilina was sentenced to a maximum of 28 years and a minimum of 21.
He will be eligible for parole in January 2032.