[1][2] Eugene, 68, and his son Gene, 30, were millionaire money lenders[3] and owners of Invincible House at 136 The Terrace in Wellington.
[4] John Barlow was a business acquaintance and made an appointment, documented in five different diaries, to meet them in their office around 6.00pm on 16 February, 1994.
Police recruited a friend of Barlow's that he had previously confided in to secretly record conversations hoping to obtain further information.
At the third trial in 1995, an FBI agent gave testimony claiming that lead content tests he conducted proved bullets from the crime scene matched those in a box of bullets belonging to Barlow that he threw away at the Happy Valley landfill the day after the murders.
John Barlow and Eugene Thomas were both members of Wellington's Wellesley Club, drank together occasionally and had known each other for years.
When he was halfway home, Barlow changed his mind and returned to the office to try and talk to the Thomases about his business idea.
[17] They searched Barlow's house and his car, and found a receipt from the Happy Valley rubbish landfill dated 17 February.
[20][1][21] Before Barlow was interviewed by the police, he called a long-term friend, and told him about finding the bodies and that he was likely to be the prime suspect.
He agreed to wear a hidden microphone to record conversations with Barlow in the hope he might make incriminating statements.
[25][24] (At the first trial, Thomas' daughter, Diane, who worked as property manager for her father, confirmed that he had been threatened by a man named Evans.
[24] Barlow told the secret witness that when he found the Thomases dead that day, he was shocked to see his gun lying there on the floor.
Despite an extensive examination of his clothing and effects by the police, no traces of blood were found, except on the briefcase that he had taken with him to the meeting.
[21] He had also filed down the firing pin and cartridge case extractor claws as well as substituting the original magazine with a homemade one.
The prosecution alleged that Barlow made these alterations in an attempt to prevent the identification of the CZ-27 pistol as the murder weapon.
[32] The defence produced a handful of witnesses who said they saw a man on the Terrace acting suspiciously around the time of the murders.
[33] The defence suggested that the Thomases were murdered by this unidentified person who used a different weapon, probably a revolver,[21] as no cartridges were found at the crime scene.
[21] They argued that Thomas Senior had attempted to use it to defend himself - he was found to have residue on his hands containing metallic elements, consistent with having fired or handled a weapon in the three hours before his death.
In this trial the defence presented Robert Barnes, an expert from Melbourne, Australia, to challenge the prosecution.
He testified that the bullets which came from Thomas Senior's body did not necessarily come from the CZ-27, but could have come from a large number of similar weapons.
[42] In July 2008, Barlow's lawyer, Greg King, took the case to the Privy Council, who ruled to hear his appeal against conviction.
[21] Peters evidence was based on lead content tests which were used to match crime scene bullets with those in a box belonging to Barlow.
Barlow's lawyer, Greg King, told the Privy council that the FBI were no longer using this test and have notified the authorities of the problem in 300 cases in which this type of evidence had been used.
[45] King argued that Peters' evidence was flawed and that his position as an FBI agent may have overly impressed the jury and influenced the weight they gave his testimony at the third trial.
[46] An affidavit by Dr. Rick Randich, a metallurgist, also gave the opinion that on the basis of the analysis undertaken by Peters, it was not possible to determine who manufactured the crime scene bullets.
He added that the unwavering support he received from his wife and family while in prison enabled him to survive the psychological impact.