Petryk, who snuck into Robert Parry's Wickham home in March, 2015, and shot him in the stomach at close range with a .22 shortened single-shot firearm, was jailed for a maximum of 26 years, with a non-parole period of 19 years and six months in Newcastle Supreme Court in 2018.

The 27-year-old from Windale, who was found guilty in 2017 of murder and armed robbery after a five-week trial, will be 43 when he first becomes eligible for parole.

Mr Parry - a well known Wickham identity and small-time drug dealer who kept his door open and was deaf in one ear - was 41.

Lawyers for Petryk lodged an appeal against his conviction in the Court of Criminal Appeal on the grounds that Justice Helen Wilson had erred in not allowing Petryk's defence barrister, Public Defender Angus Webb, to make closing submissions to the jury on matters which had not been put to the key prosecution witness, a woman who was present at the shooting and given immunity from prosecution. The issue stems from Petryk replacing his barrister, Public Defender Mark Austin, with Mr Webb towards the conclusion of the trial.

Mr Webb, during his closing address, began to put to the jury an alternative hypothesis to the one Petryk's defence had run during the trial; that he was present when Mr Parry was shot but had not been the shooter.

Mr Austin had previously advanced the hypothesis that Petryk was never inside Mr Parry's house.

During Petryk's appeal to the CCA, his lawyers argued Justice Wilson was not entitled to prevent Mr Webb from putting to the jury the alternative hypothesis - that Petryk's co-offender, Jesse Nikolovski, was the shooter. Mr Webb had suggested this hypothesis was based on the key witnesses' prior relationship with Nikolovski.

The CCA rejected the appeal, ruling Justice Wilson had made no error and her conduct constituted an appropriate control of counsel.