What has grabbed the attention of the New Zealand Innocence Project based on an American concept, academics and students at Victoria and Otago universities investigate possible miscarriages of justice is the police's manipulation of evidence.
On the way to gaining a conviction, evidence from four witnesses was withheld and the account of one, whose testimony the trial judge told the jury was "important", was changed.
That witness believes he may have been duped by the police.
These discoveries were made by Hall's family who have battled for information over many years using the Official Information Act. It has come too late for Hall who was sentenced to life and served eight years and nine months in prison, being released in June 1995.
He has always maintained that he is innocent. "He is certainly not sitting passively on the sidelines," says Innocence Project manager Dr Matthew Gerrie, "but I will tell you he is a very simple guy".
Without the efforts of his mother and brothers, says Gerrie, nothing would have happened. "He is very upset about it but he does not have the cognitive abilities to mount his own case."
During the past three years the Innocence Project has conducted a full review of the case and is collecting the last pieces of information before petitioning for the Royal Prerogative of Mercy, a process whereby the Governor-General may grant a pardon or send a case back to court.
The family unsuccessfully filed petitions based on limited information in the years after Hall's conviction.
"My personal opinion," says Gerrie, a research fellow with Victoria's school of psychology, "is that this case is one of the real shockers of the NZ criminal justice system.
"There were multiple problems with the case and we have only become aware of [all] these problems in recent times, many, many years after the conviction.
"It's a case that has flown under the radar ... that does not seem to have been picked up as one of these classical cases of miscarriages of justice even though there are these serious problems with it."
Although veteran journalist Pat Booth raised concerns in the early 1990s and Bryan Bruce featured it in 2009 in the television series The Investigator - concluding that it is the first case he has examined where he thinks the person is innocent - the case has not gained the profile of an Arthur Alan Thomas or a David Dougherty who each benefited from the help of campaigns.
Hall presents as timid. He's uncomfortable having his photo taken but obliges because it may help draw attention to the case. As the Herald is about to leave he makes the point that this is not all about him.
"Arthur Easton has been wronged twice," he says in a soft voice. "They used his murder to convict an innocent man."
Ask what he wants after so many years and he doesn't mention a pardon. "All I want is for it to go back to court to get another trial where the whole story is heard."
The whole story? Hall, who was 23, lived in a sleepout on the family property in Papakura until he went to jail. Since his release he has lived with his mother in a tiny Whangaparaoa house that Shirley Hall bought, having downsized from the family home to free up money for her son's case.
She has no doubt he was stitched up. "They [police] made up their own story and disregarded what didn't fit".
But it wasn't as though there was no evidence against Hall. Two pieces of evidence from the scene a Swiss bayonet and a woollen hat pulled from the offender's head belonged to Hall. Now 49, Hall volunteered that information to police during a routine neighbourhood doorknock but didn't help himself by giving inconsistent explanations about what happened to them lost, stolen, thrown out. Hall's explanation for those inconsistencies is that he was afraid; he'd never before been questioned by the police. The family say they believe the bayonet and hat were stolen from the sleepout earlier, along with cash and other clothing.
Hall's problems escalated from there. He'd taken a solo walk on the evening of the murder and so had no alibi.
But the police had plenty of problems too, if they were to get over the reasonable doubt hurdle and gain a conviction against Hall.
There was no blood, not a single hair from the woollen hat or a fingerprint to put Hall at the scene. During the violent struggle, one of the Easton boys clubbed the intruder over the head with a squash racket until the racket broke and yet no one from Hall's work reported any marks on him next morning.
And neither of the boys identified Hall. They had the impression the intruder was tall and dark-skinned.
Central to the Innocence Project's petition is what happened to the evidence of three motorists. They separately reported seeing a "Maori" or "dark-skinned" man running in suspicious circumstances from the direction of the Easton property about the time the 111 call was made. But neither the defence, the judge nor jury got to hear this.
Because of their location, it is unlikely the motorists saw the same man but none of the descriptions matched Hall.
Ronald Turner was considered an important witness because the suspicious man he saw was near to where a police dog tracked the intruder.
After hearing a radio report later that night about a murder, Turner rang police and described the person he saw as a "male Maori". Next day he repeated the description in a written statement adding, that the man kept looking around and ran off down an alleyway.
"When he turned around I could definitely see he was dark skinned, he was not white."
Police visited Turner again four months later - by which time Hall had become the prime suspect - and pressed Turner about whether he was sure. According to the statement taken that day, Turner said: "I am 100 per cent sure he was a Maori ... I do not feel he was a Pakeha, not even a dark skinned one."
None of these statements made it to court. Instead, the only statement from Turner that police put forward omitted all reference to colour or ethnicity and Turner was not called to give evidence in person.
The omissions were discovered after Hall's appeal had failed. A private investigator working for the family then showed Turner the version of his statement used in the court case and Turner provided an affidavit stating that a policeman had come to his house shortly before the trial with papers which he signed unread because he understood it was an accurate account of his earlier statements.
"I now note the important point that I definitely identified the person as being of Maori race has been omitted from my Court statement. I did not intend to exclude it and did not realise it had been omitted."
"I am extremely surprised ... particularly after the Police Sergeant had tested me at length on this very point, and made an issue of it.
"I still believe that the person I saw that night was a Maori person and that would have been [my] evidence if called to court, and the police certainly knew that I was definite in that identification.
"I am now aware that my statement was read to the jury in the trial of a European. I know that the person I saw running across Clevedon Road that night was not a European."
The trial judge, Justice Pritchard, thought Turner's statement cogent enough to read it in full to the jury during his summing up the third time it was read during the trial.
"It is an important piece of evidence," the judge told the jury. "I think I should read it to you because, it has quite a bearing ... "
After reading it, the judge added that Turner "certainly saw a man running in suspicious circumstances in the right vicinity at the right time".
As well as being in the dark about the evolution of Turner's statement, the judge, jury and defence did not know that:
Turner's wife, who was in the car with her husband but did not see the man, told police her husband had said "look at that Maori guy over there, he looks suspicious. It looks like he's just done a robbery or something".
Motorists, William Cossey and Michael Bungard, reported seeing men they described as "Maori" or "dark-skinned" running a short distance away across Clevedon Rd.
The Hall family's long inquiry indicates the police were not short of leads regarding other suspects.
Two days after the murder, an anonymous female left a message on the answerphone of the Papakura police. "I have got to say this in a hurry go and see X X and X X [names deleted by Herald]. It's them."
Graffiti on a local building linked an associate of the men named by the anonymous caller. The Hall family say one of the men has a conviction for an intruder crime and another was a suspect.
They don't believe the police investigation properly investigated their alibi.
"I struggle to comprehend the reasons why the Crown brought this case to the courts," says Hall's brother Geoff, a company manager. "It simply cannot be for justice, because justice demands the truth, the whole truth."
