The brother of American mathematician Scott Johnson says he has accepted the possibility of having to sit through a trial for the man who unexpectedly admitted to his 1988 murder but is now appealing.
Scott Phillip White took his lawyers by surprise by declaring "guilty, I'm guilty" during a pre-trial hearing in January.
The 52-year-old was awaiting trial after being arrested decades after Scott Johnson's body was found at the base of cliffs at North Head.
White's lawyers unsuccessfully attempted to withdraw the plea and he was subsequently sentenced to 12 years in prison.
But he is now appealing against his conviction by arguing a Supreme Court judge erroneously denied the application to withdraw the plea.
Scott Johnson's brother, Steve Johnson, once again travelled to Sydney from the United States to attend the proceedings in person.
"I think it always matters that I'm in the court," he said outside the NSW Court of Criminal Appeal after a two-day hearing.
Steve Johnson said he believed the judges needed to see the importance of the matter to his family, in addition to investigating police who joined him and the legal team working on the appeal.
"I have to say, this time around it was hard," he said.
"There was a lot of detail in the accused's circumstances and the information that he had to process in order to make his plea and so I had to relive that again, it was pretty gruelling."
If the appeal is successful, White is likely to face a trial over Scott Johnson's murder.
"That is a possibility, I've accepted it," Steve Johnson said.
"I think there's no way around the fact that I'm disappointed that my brother's case is still not settled, but I can see the importance of what's taking place in the court this week."
White had essentially "convicted himself", Mr Johnson added, so looking closely at the circumstances of the plea was "tantamount to assuring him a fair trial".
"Seeing the care that has been taken to be sure the defendant is well treated, I respected that."
During the appeal, White's lawyers argued the wrong legal test was applied in determining whether or not he should be allowed to withdraw his plea.
They also said it came at a time when the Crown case had not been particularised and highlighted his consistent prior denials of the offence.
But the NSW Director of Public Prosecutions, Sally Dowling SC, on Wednesday told the hearing White received "very, very high level and proper legal advice from the day of charge".
She also pointed to expert evidence, including from a neuropsychologist who said that while White was functioning in the range of someone with "an intellectual disability of mild severity", he could convey a clear understanding of the nature of the charge and the meaning of guilty and not guilty.
The appeal judges reserved their decision.
Steve Johnson said he would return to Australia for the judgment.
"My daughter called me this morning from America," he said.
"She was six weeks old when her uncle died, she just turned 34 this week.
"She said 'I hope this is the last time you have to come to Australia in a suit'."
