Murder of Harvey and Jeannette Crewe

In 2014 an official police review of the investigation into the homicides, at a cost of $400,000 to New Zealand taxpayers, said that evidence available in the murder of the Crewes was insufficient for any new prosecution. The review acknowledged that a key prosecution exhibit in the trials had been fabricated by detectives, but did not appear to accept that they could have been on the wrong track; the review implied that the Crewes' daughter had not ingested any fluids between 17 and 22 June, and said a witness had been mistaken in thinking he had seen a woman on the farm during that period. The review did however rule out Demler having been the killer. Rochelle Crewe expressed satisfaction that a police review of evidence had cleared her deceased grandfather of involvement in the murders. The case remains unsolved.

A Royal Commission of Inquiry was ordered to review the wrongful conviction of Thomas and reported to the Governor-General in November 1980. The Commissioners found that the spent cartridge case from Thomas's gun, Exhibit 350, 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. The Commission's report implicated Detective Inspector Bruce Hutton and Detective Sergeant Lenrick Johnston in police misconduct, and found that the prosecution of Thomas for the murders had been unjustified. Despite the Commission describing the conduct of Hutton and Johnston as an "unspeakable outrage", the New Zealand Police never laid charges against any officer involved in the investigation and prosecution of Thomas. Johnston died in 1978. Hutton died in 2013. The case was made into the docu-drama feature film Beyond Reasonable Doubt in 1980.

Despite his wife and cousin giving him a strong alibi for 17 June, Thomas was sent for trial on a charge of murdering the Crewes. The prosecution suggested Thomas's wife, Vivien, had been the woman seen at the Crewes' house, although she was not charged. The witness was certain Vivien Thomas, whom he knew, was not the woman whom he saw. The prosecution said that the motive for the murders was that Thomas had been obsessed with Jeannette, an accusation for which they provided very little evidence. A witness who did give testimony supporting the prosecution's contention that Jeannette had been pestered by Thomas was Demler; he was cross-examined about why he had not mentioned such obviously relevant information before the court had begun sitting. Thomas was found guilty of the murders in a 1971 trial, but the conviction was overturned on appeal. He was tried again in 1973 and convicted. Supporters of Thomas started a campaign to bring to public attention that the key evidence against him had serious anomalies.

In 1970, the Crewes and their 18-month-old daughter lived on their farm at Pukekawa, Lower Waikato. Jeannette was afraid to be in the house without her husband after bizarre burglary and arson attacks, including one in which clothes were set on fire in a bedroom. At the time of her death, Jeannette was about to receive her mother's half-share in the Demler farm, which adjoined that of the Crewes. The bequest to Jeannette had come about after Jeannette's sister had been cut from their mother's will, and Demler had removed Jeannette as a beneficiary of his own will in retaliation although she had no role in the original matter. Jeannette's mother had then re-written her will to bequeath to Jeannette the half-share in Demler's farm that he lived on.

Harvey (28), and Jeannette (30), were found to be missing from their bloodstained farmhouse on 22 June 1970 by Demler (died 4 November 1992), who had been asked to look in on them by an alarmed neighbour because they had not answered the telephone for days. The Crewes' 18-month-old daughter Rochelle was distraught in her cot. Demler left her alone while he went on a farm errand. The Crewes had last been seen on 17 June, and milk, bread, and newspaper deliveries on the morning of 18 June had not been collected from the letterbox.

Jeannette Crewe's father, Lenard M. Demler, was fined £10,000 for tax evasion in 1962, and had been forced to sell a half share in his farm to his wife in order to meet the liability. Jeanette married her husband, David Harvey Crewe (known as Harvey), in Auckland in 1966.

David Harvey Crewe (20 October 1941 – c. 17 June 1970) and Jeannette Lenore Crewe (née Demler; 6 February 1940 – c. 17 June 1970) were a New Zealand farming couple who were shot to death in their home around 17 June 1970. The murders led to the wrongful conviction and subsequent pardoning of another farmer who lived nearby, Arthur Allan Thomas. A Royal Commission set up to investigate the miscarriage of justice found that a detective had fabricated evidence and placed it at the scene of the crime. No person was ever charged with planting the evidence, and the murders remain unsolved.