Two young men have been found not guilty of the murder of 56-year-old Canberra man Peter Keeley.

Mr Keeley's body was found in bushland at Broulee, on the New South Wales South Coast, on February 2, 2020.

Three 17-year-old boys were charged with his murder at the time.

Two of them, now aged 19 and 20, faced a six-day judge-alone trial in the NSW Supreme Court in May after pleading not guilty to murder but guilty to aggravated kidnapping.

Today, Justice Michael Walton found them not guilty of murder but convicted them for detaining Mr Keeley with the intention of occasioning actual bodily harm.

During the trial the court heard one of the accused spoke to Mr Keeley on the Grindr dating app before he was found dead and that another thought he was a paedophile.

There was disagreement between the two forensic pathologists who took the stand, including over whether Mr Keeley's airways were obstructed before his death and what his cause of death was.

In his evidence for the prosecution, Bernard I'Ons told the court Mr Keeley likely suffered cardiac arrest caused by a craniofacial trauma with airway obstruction after the teenagers assaulted him.

But defence witness Johan Duflou argued that methamphetamine in Mr Keeley's system could have contributed significantly to his death.