On the night of Sunday, 13 October 1985, a 52-year-old father of five, Arthur Easton, was stabbed to death in his Papakura home.
His teenage sons, Brendan and Kim, were injured in the attack but survived.
The boys initially described the attacker as a strong six-foot (1.83m) Maori man. Police searched for this suspect for months, but in the end, the man arrested, charged and incarcerated for Arthur's murder was Alan Hall - a slim, 1.7m Pakeha with learning difficulties.
Hall has always maintained his innocence. More than 30 years later, he is still in prison.
His family believe evidence was tailored to frame Hall, a claim that is firmly rejected by police and prosecutors.
The night of the murder:
The facts of what happened on the night of the murder are still contested, but there is an undisputed sequence of events.
At approximately 8pm, 16-year-old Papakura High School student Brendan Easton was studying in his room.
His dad, Arthur, was watching TV 6m away in the living room, and his older brother, Kim, was in his own bedroom.
Brendan heard the back door click. He went to investigate and discovered an intruder in the spare room by the back door. He shoulder-charged him to the bed and then retreated into the hall.
According to his police statement, Brendan screamed for his dad, and Arthur rushed to the hallway to try and restrain the intruder.
Kim Easton later told detectives that he also rushed over and punched the stranger. He smashed a squash racquet down on the offender's head until the frame snapped in half.
During the attack, Arthur Easton was stabbed multiple times. The offender managed to escape, leaving behind three pieces of evidence - a bloodied bayonet, a woollen beanie and a single muddy footprint.
Brendan Easton called emergency services at 8:05pm, Arthur Easton died at approximately at 8:35 pm. The scene was declared a homicide at 8:37pm.
This is how the scene of the crime appeared in the moments after the intruder fled.
The bayonet used to kill Arthur Easton and the woollen hat worn by the intruder were both later traced back to Alan Hall.
An unlikely suspect:
On September 27, 1986, 24-year-old process worker Alan Hall was found guilty of the murder of Arthur Easton.
The prosecution's case rested on a few key facts:
Hall had no alibi for the night of the murder.
The murder weapon belonged to him.
The woollen hat left in the scene belonged to his brother.
He gave inconsistent explanations for how those items ended up at the crime scene.
Hall eventually told police that both the bayonet and hat had been stolen from his house a month before the killing. He said he hadn't reported the theft because he was still grieving the recent death of his father.
His lawyers argued he had no motive and didn't know Arthur Easton. There was no forensic evidence linking him to the scene. Despite the offender being punched repeatedly and hit with a squash racquet, Hall's family and work colleagues never saw any injuries on him.
Hall's barrister also described him as "intellectually backward" to explain his inconsistent stories to police.
On the evidence statements Hall signed the day police first questioned him, he spelt his own name incorrectly on every page.
The defence also argued that it was extremely unlikely a man of Hall's size could overpower three men who were all significantly larger than him.
And as Newshub Nation discovered, a crucial piece of evidence was withheld from the jury and Hall's defence team during the original trial.
Watch the video for the full investigation from Mike Wesley-Smith.