For 9 years, Arthur Thomas was imprisoned for the murders of Harvey and Jeannette Crewe. He was innocent.

In New Zealand, there is one cold case murder in particular that is deemed one of the most infamous of all. 

It centres around the murders of Harvey and Jeannette Crewe. In June 1970 their killings were labelled by many as 'the death of innocence' in New Zealand.

In June 1970, Jeannette and Harvey Crewe were found to be missing from their farmhouse in Pukekawa, situated between Auckland and Hamilton.

For three days their family and friends hadn't heard from the couple, so Jeannette's father went to the home to check on them. He was met with a disturbing scene. A bloodstained carpet and rearranged furniture were evidence of a struggle. The only person found in the home was the couple's 18-month-old baby Rochelle, found seemingly unharmed in her cot. She had been left alone for just under a week.

In the immediate aftermath, a man was charged and found guilty of the crime. But after serving nine years in prison, he was granted a royal pardon and found to be innocent.

The question of who really killed Harvey and Jeannette Crewe remains to this day.

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According to all reports, Harvey and Jeannette Crewe were an ordinary, well-to-do couple from a regional town.

Leading up to the murders, the Crewes had reported to police that their home had been burgled, as well as two fires being deliberately lit on their property.

"That really unnerved them. Particularly Jeannette, she was really nervous to be at home by herself, and she would kind of follow Harvey around the home," Kirsty Johnson — an award-winning investigative journalist — told Mamamia's True Crime Conversations.

These sorts of crimes were rare in their local area, so according to Johnson, the couple had valid reason to feel they were being targeted by someone. 

On June 16 1970, Jeannette's dad went over to their house for dinner. It was only days later when he went to do a welfare check on the couple and their young daughter, and was met with the bloodstained carpet and rearranged furniture.

A point of confusion among investigators is that when Jeannette's dad Lenard Demler found Rochelle in the house, he left her there, drove to a nearby neighbouring property and got that neighbour to check out the scene with him for assistance. The fact he left Rochelle in the house, despite the alarming crime scene, was unusual police said.

"Lenard basically said that he panicked, and he wanted to get out of the house," Kirsty Johnson explained.

The bodies of the Crewes were eventually found in the Waikato River, and it was determined that the pair had been shot in the head with a .22 long rifle. They had been murdered on June 17, 1970, and their bodies were found some weeks later.

When it came to how baby Rochelle managed to survive, it was perplexing. 

Experts say there is no medical opinion to suggest an infant could survive without fluids for five days.

Given the Crewes were murdered on June 17, Rochelle would have been left alone for five days. The fact she survived those five days resulted in speculation that she had to have been looked after to some degree during that time. This was based on tests that showed she had not ingested fluids for at most two days before she was found, rather than five days. 

"This is one of the central mysteries of the entire case," Kirsty Johnson said on True Crime Conversations.

"She was really dehydrated but not so bad that she wasn't okay. She was given cream for nappy rash and some fluids. A young labourer in a paddock nearby told police he had seen a woman standing at the front of the Crewe property on the morning of June 19 who was dressed in slacks, and had light brown hair."

There was then a second sighting of this supposed mystery woman as well – a local telling police she had seen "a fair-haired girl" near the property. 

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Initially, police zeroed in on Jeanette's father, Lenard Demler. Kirsty Johnson saying police "spread rumours" about Demler being the culprit.

Jeannette's blood type was found on his car seat, and Demler did have a scratch on his neck. Police were also told that Demler probably had access to an unregistered .22 calibre weapon. However, the evidence against Demler was entirely circumstantial, despite strongly denying any knowledge of what had happened to his daughter and her husband.

Eventually, the police would circle in on one man in particular — Arthur Allan Thomas.

A car axle linked to the Crewe's neighbouring farmer, Arthur Allan Thomas, had apparently been used to weigh down Harvey's body and was central to police theories about the case.

To find the gun used to kill the couple, police collected and test-fired 64 registered .22 firearms in the area. Those 64 registered guns reportedly only made up three per cent of the total guns reportedly held in the Pukekawa area.

From that test, Thomas' rifle couldn't be eliminated as a possible murder weapon. Along with the car axle likely belonging to Thomas, police believed he was the killer. Despite his wife and cousin giving him a strong alibi for June 17, Thomas was sent for trial on a charge of murdering the Crewes.

Months after the Crewes' death, the Crewe house was searched for a third time and a cartridge case was found. Police used this cartridge case to convict Thomas with murder.

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In 1971, he was found guilty and sentenced to life in prison. The conviction was overturned on appeal soon after, and he was tried again in 1973 and convicted. He ended up serving nine years in prison. 

But campaigners fought back against the conviction, following evidence and forensic work that showed the cartridge case had been planted at the scene by police.

Thomas was pardoned by the Governor-General in 1979 and released after serving nine years in prison. He was paid NZ$950,000 compensation for his time in jail and the loss of his farm.

A Royal Commission of Inquiry was ordered to review the wrongful conviction, and found the cartridge case had not been left by the murderer, but had been created weeks later by police, using his impounded gun and ammunition, then planted at the Crewe farmhouse.

Despite these findings, the New Zealand Police never laid charges against any officer involved in the investigation and prosecution of Thomas. His lawyer described the case as a turning point in New Zealand history which left the reputation of the police tarnished forever.

In 2014, an official police review implied that the Crewes' daughter Rochelle had not ingested any fluids between 17 and 22 June. They also said the witnesses had been mistaken in thinking they had seen a woman on the farm during that period. 

The review also ruled out Demler, Jeannette's father, as having been the killer.

As for where this all leaves the cold case now — it remains unsolved. It has been more than 50 years since the murders took place, leaving the Crewe's daughter Rochelle without justice. 

As Kirsty Johnson said to True Crime Conversations: "It probably won't be solved. Most people who knew about it have died by now, and if somebody can keep a secret for 50 years – then it just really felt to me like they would always keep that secret. However, it does remain open."

The photo included in this article serves as the primary means of visual identification of the subject. There is no known free equivalent of this portrait, so the image cannot be replaced by a free image. The photo's source is traced and credited here.

Feature Image: Wikipedia.

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