The lawyer for double murderer John Barlow is confident the Privy Council in London will quash his convictions after it agreed on Tuesday to hear his appeal.
Financial dealers Eugene and Gene Thomas were killed in February 1994, and Barlow was convicted in 1995 after three trials for their murders. He is serving a mandatory sentence of life imprisonment with a minimum non-parole period of 14 years.
Barlow's lawyer, Greg King, appeared before the Privy Council on Tuesday to request the hearing.
Barlow's wife, Angela, says the appeal will be based mainly on evidence by the FBI that was introduced in the third trial. She says it has since been totally discredited.
Mr King says he is confident new evidence he will present will quash the conviction and that there will be no retrial.
No date has been set yet for the hearing, but it is likely by April or May.
Eugene and Gene Thomas, father and son, were found shot dead in their offices in the Invincible Building on The Terrace in Wellington.
The main suspect was Barlow, who was seen leaving the building about the time of the murders. Barlow contacted the media before his arrest to publicise his claims of innocence. He said he had seen the bodies and left immediately, telling no one for fear of being blamed.
After Barlow's arrest, police found that the diary on Eugene Thomas' desk had a page removed for the day of the murders. Through a documents expert it was established that the missing page had recorded an appointment with Barlow at 5.30pm.
Barlow gave different accounts of what he had seen and heard on the day of the murders.
In one account, he said Gene Thomas asked him to return later and he left. In another, he said he heard a gunshot when he was leaving, and on his way home decided to return and investigate. He found the pair dead and left the scene.
The first trial began in 1995. The primary piece of police evidence was Barlow's pistol, silencer and ammunition.
This had been recovered from the Happy Valley rubbish tip, after police found a receipt in Barlow's belongings for the tip dated a day after the murders.
The pistol had a .22 calibre barrel, but the Thomases had been shot with a .32 barrel weapon. It was established that the pistol was designed to take a .32 barrel, but this was not located.
The court heard that Barlow had told a friend he had found the bodies when he turned up for the meeting. He said he had earlier lent Eugene Thomas the pistol and found it lying next to him. Thinking the murder weapon would be traced to him, he decided to get rid of it.
Hung juries at two trials
At the first two trials, the defence pointed to a lack of motive, even though Barlow was known to have a big loan with the Thomases' business and was in financial hardship.
Because the .32 barrel was never found, it was not conclusively established that Barlow's pistol was the murder weapon. The defence also provided expert testimony that the bullets found in the bodies could not have been fired from the pistol. Both trials ended in hung juries.
A third trial took place in October 1995 when new evidence from the prosecution was introduced. This negated the defence's contention that the bullets could not have been fired from the pistol.
The new study and testimony said the pistol could have fired the fatal shots and the bullets found at the tip were the same type as the bullets in the bodies. This was strongly contested by the defence.
Barlow was found guilty of both murders. Later the Court of Appeal upheld the verdict, expressing confidence in the third jury's decision.