Arthur Allan Thomas has been required by police to provide an alibi for the night Harvey and Jeanette Crewe were murdered.
Thomas was eventually pardoned for the June 1970 murders, but not before he spent nine years in prison for them.
According to the Weekend Herald, Thomas, along with two of his brothers, his sister and her husband have all been re-interviewed by police and had to provide details of their whereabouts on the night of the killings.
A member of the family also reportedly said officers had told them that they still believed Thomas' rifle was the weapon that carried out the double murder.
But it is the rifle of his brother, Richard Thomas, that police have taken away for testing this month, according to the Herald.
The family told the Herald they had "no idea" why police were interested in that gun.
Thomas was interviewed by police on August 16, and was asked, among other things, whether or not he went rabbit shooting on his own and if his brother-in-law Buster Stuckey had access to his farm.
Detective Superintendent Andy Lovelock and Detective Senior Sergeant Gary Lendrum conducted interviews with Thomas' sister Margaret Stuckey and her husband Buster.
She said the questions were very "pointed", and at one point the officers told her the evidence still pointed toward Thomas as the killer.
Thomas was convicted in two trials - in 1971 and 1973 - of the killing of the Crewes at their Pukekawa home, but was pardoned nine years later.
A Royal Commission of Inquiry in 1980 found Hutton and one of his detectives, Len Johnston, faked evidence against Thomas by planting a cartridge case from Thomas' rifle at the murder scene.
The commission also found neither Thomas nor his rifle were involved in the murders, and Thomas received nearly $1 million incompensation.
Hutton never accepted the commission's finding and admitted no regrets for any of his actions.
He died earlier this year.
When Hutton died, Deputy Police Commissioner Mike Bush delivered a eulogy at the funeral quoting a 1967 comment from Hutton's service file that "his integrity is beyond reproach".
Thomas criticised police, saying the comment showed continued bias against him and he now had no faith in a police review of the Crewe case.
Police Commissioner Peter Marshall also refused to accept the Commission of Inquiry's findings.
At the time, Leading civil liberties lawyer Gary Gotlieb said he was not surprised by Marshall's stance.A spokesman said on his behalf: "The appropriate time for us to make further comment will be when the review is completed" and "we will not pre-judge the outcome of the review which is why we are not in a position to comment further ahead of it being completed".
Gotlieb said it would have been refreshing if police had acknowledged wrongdoing in the past.
"The culture needs to change, because you can always get it wrong," he said.
In 2010 Rochelle Crewe - the only daughter of Harvey and Jeanette - asked police to reopen their homicide investigation to find the killer.
Police refused to reopen the case, but Deputy Commissioner Rob Pope to reassess the homicide file in a bid to get her the answers she needed.
Rochelle was just 18 months old when her parents were killed, and was found crying in her cot five days after they were last seen alive. It is thought someone had been looking after her and feeding her throughout that time.
- © Fairfax NZ News
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