As a result, Justice 'Lang said he had been forced to draw his own conclusions on what had occurred.
He said their relationship was "at times testy" but it was evident that they had been friends.
Fahey had 202 previous convictions starting from when he was 17. He also had a history of carrying knives with him and consequently had been subject to many sentences of imprisonment, Justice Lang said.
Fahey was quick to react and reacted violently when he did, he said.
"You have a streak of viciousness underlying your usually civil veneer," Justice Lang said.
Mr Harris' sister Michelle Harris today read a victim impact statement to the court, saying that their mother suffered a stroke shortly after her brother's murder, an event she believed was brought on by brother's death.
Their parents had suffered incredibly since, she said.
"At the age of 53, I never thought I'd have to speak of my murdered brother," Ms Harris said.
"It sickens me to know that a vicious attack on my brother was carried out by someone he thought was a friend."
At the trial, the court heard that on the night of the murder, Fahey and Mr Harris had been at a friend's apartment on Symonds St before they left to get pizza.
Shortly after they got to Myer's Park, Fahey stabbed Mr Harris four times with a knife that was about 22cm long - once in the arm and three times in the upper chest, penetrating his heart and lung.
Prosecutor Josh Shaw said Mr Harris tried to escape Fahey after the first blow but the killer caught up with him and continued the attack.
Afterwards, Fahey returned to the apartment but was asked to leave due to his erratic behaviour.
His friends told police he was sweating, breathless and rambling about blood on his clothing.
He later walked into the Central Auckland station with a lawyer to hand himself in for the murder of Mr Harris.
Killer had earlier conviction for assault on Asian couple
Fahey had been released from prison 41 days earlier for a brutal attack on a young Asian couple in almost the same place.
The Herald can now reveal that Fahey was sentenced to one year and three months in jail for an incident in the same park, which is 450m from the Auckland Central police station, on December 31, 2011.
Grenville Kookie Fahey.
Court documents released to the Herald reveal Fahey racially abused an Asian couple as they walked through Myers Park.
He did not know the couple, but confronted them, became aggressive and threatened to kill them.
"[Fahey] pulled out a rock which was inserted in a sock and held it firmly gripped in his hands," the police summary of facts stated.
"[He] then began swinging the sock with the rock inside it over his head, [and it] began to pick up speed ... then reached forward and propelled the rock whilst still holding on to the sock, hitting the back of [the male victim's] head, causing him to fall to the ground."
Fahey then approached the injured man's girlfriend and said: "I f**ken hate you Asians, I'm gonna f**ken kill you."
She called police, who arrived quickly and found Fahey "in an intoxicated state".
Officers had to restrain Fahey, who gave no explanation for his actions.
In July 2013 Fahey pleaded guilty to assault and threatening to kill. He was sentenced the same day, but the 18 months he spent in custody on remand was considered time served and he was convicted and released.
He killed Mr Harris 41 days later.
There is no indication in Judge Geoffrey Rea's sentencing notes from the earlier offending, also released to the Herald, that Fahey was to be monitored or supervised in any way, nor to attend any post-prison programmes or treatments.
After his release he did not come to police attention until he walked into the Central Auckland station with a lawyer to hand himself in for the murder of Mr Harris.
