After completing a four-year review, NZ Police has apologised to Rochelle Crewe over the investigation into her parents' deaths.
Harvey and Jeannette Crewe were murdered at their Pukekawa farm in 1970. Police say they still don't know who did it.
Arthur Alan Thomas was convicted of the murder in 1971 but pardoned in 1979.
A Royal Commisison of Inquiry found the officer in charge of the investigation, Detective Inspector Bruce Hutton, and one of his investigators, Detective Lenrick Johnston, as being guilty of corruption.
Today Police Commissioner Mike Bush said while the review wasn’t able to answer all questions, the police now have the best possible knowledge of the case. (See reports and video of the case attached)
The review was sparked by the Crewes' only daughter, who was a baby when her parents were killed.
Mr Bush says the police apologise for a number of identified shortfalls in the original investigation that led to missed investigative opportunities and allowed for continuing public speculation and commentary over the years.
“Police deeply regret the anguish this has caused Rochelle and family members," Commissioner Bush says.
The apology also encompassed the fact that Police did not conduct an assessment and review of the original investigation either after Mr Thomas was granted a free pardon or after the Royal Commission of Inquiry released its findings.
A key finding was that there was a “distinct possibility” that the cartridge case used to implicate Mr Thomas may have been planted, and is so police were likely to have been responsible.
The report released today found the crime scene was poorly managed from the outside, there may have been scene contamination.
It also found the initial scene reconstructions did not fully explore all possible scenarios.
Leading QC David Jones, who independently reviewed the report, agreed with the conclusion that no person could be identfied as the offender.
Mr Jones' report also says there would have been enough evidence to launch a prosecution against Hutton if he had still been alive.
He says, however, the Royal Commission was so damning it would have been difficult to run a fair trial in the 1980s, as a jury would have been affected by the findings. He says there would have been merit in a stay on those proceedings.