In his closing remarks to the jury, Senior Crown Prosecutor Peter Barnett alleged Karen Dawson and her son Matthew Aquilina were involved in a "criminal enterprise" which bailed Adrian Trevett up in an old Butter Factory for several hours and questioned him before he was strangled to death with a noose.
The trials of the two accused have been running at Newcastle Supreme Court since late August.
The court heard Mr Trevett was picked up by Ms Dawson (his friend and neighbour) after a bike ride to the Gibraltar summit from Glen Innes when he was allegedly taken back to the old butter factory questioned and assaulted before he was killed.
The pair allegedly put his body into a car and dumped it into bushland near Tenterfield with the rope still wrapped around his neck.
Mr Trevett was reported missing by family members two weeks later, but his body wasn't found until January last year.
Aquilina, had earlier pleaded not guilty to murder but guilty to manslaughter siting provocation as his defence.
The Crown told the jury they had already heard "clear admissions" of Aquilina's involvement in the murder but Aquilina wanted the jury to accept that he was provoked into the killing when Mr Trevett made a comment to him when he was being questioned about children.
He said what Aquilina was doing at the butter factory was "coldly and calculatingly executing this man."
The court heard Aquilina was previously told of allegations of child sexual assault against Mr Trevett.
"He doesn't even have 100 per cent faith in what he's being told by his mother," The Crown said.
"If it's about being provoked then why is it (that) the first time he lays eyes on him he cleans him up with an iron bar."
He said Aquilina had placed the rope around Mr Trevett's neck and pulled on the rope until he "gasping" for air and passed away.
He told the jury the actions were done "with intent to kill."
The crown said it was also up to the jury to decide if the alleged involvement of Dawson was also as a result of provocation.
When addressing the jury, he said there was previous evidence to the court that Dawson alleged Mr Trevett had assaulted two young children and on one occasion she allegedly he tried to sexually assault her.
Ms Dawson's defence barrister said she had told friends and her son Matthew on previous occasions that she was being sexually harassed by Mr Trevett.
She said initially Ms Dawson had taken the blame for the killing to protect her son, but it wasn't until a walk through of the burial ground with detectives that she had broken down and told police she didn't commit the crime. The defence said Mr Aquillina had done the "exact opposite" and "portrayed himself as the good guy."
The court heard while Mr Trevett was being questioned in the old butter factory, Dawson had punched Mr Trevett at least once.
The defence said when Dawson punched Mr Trevett to the side of the head, it was the first time she had punched anyone in her life.
The Crown alleged once Dawson punched Mr Trevett she had become a "party" to and an "active participant" to the alleged enterprise and was therefore liable for Mr Trevett's murder.
He said even if Dawson didn't pull on the rope which killed Mr Trevett she remained at the scene and did nothing.
The defence alleged Dawson had told her son not to pull the rope around Mr Trevett's neck but he was "too angry."
The crown alleged the butter factory was cleaned with chemicals after Mr Trevett was killed.
He said it was a matter for the jury to determine if Ms Dawson was provoked by Mr Trevett by his previous conduct or his conduct on the day and whether or not she lost self control.
Aquilina's defence will address the jury on Thursday morning.