Justice has never been served for them or their families, and while in some cases police are confident that one day they will get a result, others will never be solved.
Police provided the Herald with details of each of the unsolved homicides from 1914.
Since then there have been a number of other murders, with only one unsolved to date.
As we remember those killed, we urge anyone with information on these cases to contact their local police - or offer details anonymously via Crimestoppers - and help them solve the mystery of what happened to the 66.
Diana Leafa, 23, was reported missing on September 17 and police and her family said they had serious concerns for her safety.
Twenty two days later, on October 9, her body was found.
Leafa was naked and lying in tussock-covered sand dunes at remote Waiinu Beach settlement, just outside Waitotara township.
Where her body was found is remote and nearly 40km from where she was last seen alive.
Leafa worked as a prostitute, which upset her deeply religious family.
However, they spoke out after her death in a bid to help police find answers.
Police have previously said that they have not completely ruled out Leafa's death was an accident - but that, as time went on and nobody came forward with information about her final hours, they considered it less likely.
Katrina Ann Jefferies July 12, 2005 Auckland
The 22-year-old solo mother was last seen about 8pm on July 10, when she left the suburban home she shared with her mother and 20-month old son.
Police at the time said their stories about what happened to their baby were riddled with inconsistencies - such as Waru telling police that Staranise had banged her head on a door at a video store while he was with her.
But police said video footage from the video store did not support this, and Waru later changed his version of events to say that Staranise had hit her head on a car door.
At a Coroner's inquest the pair were called to give evidence.
Hopa told the court that she did not know what happened to her daughter.
Under questioning both Hopa and Waru repeatedly answered that they could not recall events around their child's death, or opted not to answer on the basis they could incriminate themselves.
The unemployed beneficiary, who was known to be a heavy drinker and illicit drug user, was killed by blunt-force trauma to the head.
He was found by police on his bed at 8pm the next day.
Police said there was evidence the house - owned by a notorious drug dealer - was cleaned and Allen's body moved before 111 was called nearly 24 hours after he was believed to have been fatally injured.
Fewer than 10 people were at the house on the night Allen died and police said at the time there were "obvious gaps in honest information" in what those people were telling police.
Jordan Voudouris June 17, 2012 Paeroa
Jordan Voudouris was murdered at the back of his pizza shop.
Allison lived alone in the house but police were seeking information about a blue Nissan driven by a middle-aged European woman around the time of the death.
Atreyu Taylor-Matene July 13, 2013 Kamo
Atreyu Taylor-Matene died in Starship children's hospital after suffering serious head injuries at the Northland home where he lived with his mother and her partner.
He was just 1.
Almost 30 police worked on the initial phase of the investigation, which included a forensic examination of the house where Atreyu was fatally injured.
Hayward was last seen leaving his home around 5pm, with the intention of travelling to the family bach in Raglan.
He never arrived.
He was initially coded as a missing person but in 2017 police revealed that new information had come to light and Hayward's disappearance was considered a homicide.
"We now believe something sinister may have happened to Rick," said Detective Sergeant Andrew Saunders.
"It may be the case that Mr Hayward was the victim of a hit and run. We are not suggesting that anyone deliberately knocked him down.
"However, the driver might have panicked and disposed of Mr Hayward's body."
Emergency services responded to a report of a baby suffering a head injury and breathing difficulties at a dairy farm near Burnham, 30km south of Christchurch, at 6.45am.
Soul Mathew Turany was flown to Christchurch Hospital by Westpac Rescue Helicopter in a critical condition.
He was taken off life support just after 3am the following day.
In October the same year police confirmed Soul's death was being treated as a homicide.
He handed over the cannabis, but when he came back downstairs he found Fraser wounded on the floor.
Fraser died at the scene, and had suffered a blunt-force injury to the top half of his body.
Investigators have spoken at length with more than 50 people, including associates of Fraser's and possible witnesses, but to date, no information has been found that would lead to the identification of the offender.
Alestra Kepa-Hati September 25, 2016 Kaikohe
Alestra, 4, was in the care of Child Youth and Family in Northland when she died.
She reportedly suffered a minor seizure, fell and hit her head.
They believe that the four people who barged into Tolley's home were attempting to carry out some form of "taxing" or debt collection, or that they were looking for drugs and/or cash for their own use.
Roma Midwood May 1, 2017 Tirau
Midwood, more commonly known as Roma Joseph, died in a deliberately lit house fire. She was home alone when somebody set fire to the home between 3am and 3.30am.
He was a Killer Beez gang member who was released from prison just two months before his death, following a four-year sentence for injuring, intentional damage, possessing a firearm and unlawfully getting into a motor vehicle.
Police initially said they weren't looking for anyone else in relation to the shooting, which they described as "unexplained" but later confirmed a homicide investigation was underway.
His 20-year-old partner Kahlee and a 17-year-old man, believed to be a family friend, were also seriously injured.
His sister Erin said they believed the attack was random or a case of mistaken identity by a gang. She stressed her brother was an "innocent person caught in the crossfire".
"Somebody arrived to the house and attacked about four people inside. There was another person holed up inside who wasn't injured," she said.
Her brother had died "covering his girlfriend" from the bullets, Erin said.