Officers have told the family that they still believe Mr Thomas' rifle was used to shoot the young couple at their Pukekawa farm in June 1970, despite his being cleared of the double murder.
His family say they are horrified that the police are still pursuing and "harassing" them, instead of finding out who really killed the Crewes.
Mr Thomas was found guilty of the murders in 1971 and again at a retrial in 1973. But in 1979, after he had spent nine years in prison, he was granted a pardon on the basis that the police case against him was not proved beyond reasonable doubt.
In 1980, a royal commission of inquiry found that the police planted evidence that was used to wrongly convict Mr Thomas and that the farmer should never have been charged with the murders.
The commission said neither Mr Thomas nor his rifle was involved in the murders, which remain unsolved. He was later paid $950,000 compensation.
In 2010, the Crewes' only child, Rochelle, asked police to reopen their homicide investigation in a bid to find out who killed her parents.
Rochelle was 18 months old when they died. She was found crying in her cot five days after they were last seen alive.
Police refused her request, but Deputy Commissioner Rob Pope agreed they would conduct a "thorough analysis and assessment of the Crewe homicide file in an endeavour to answer questions raised by Rochelle Crewe".
But this month, almost three years on, the senior officer charged with carrying out the review, Detective Superintendent Andy Lovelock, began asking new questions of the Thomas family, including demanding alibis for the night of the murders from Arthur Thomas' sister Margaret Stuckey and her husband Buster.
Police also visited Mr Thomas' brother, Desmond, and took a rifle away for "testing". The rifle belongs to another brother, Richard Thomas, who has also been interviewed by police.
It is not the same rifle initially identified as the murder weapon, which belonged to Mr Thomas, and his family "have no idea" why police are interested in the second gun.
Police interviewed Arthur Thomas at 11am on August 16, and asked him about Mr Stuckey.
He told Desmond Thomas police asked him, among other things, if, around the time of the murders, he went out rabbit shooting at night on his own and whether Mr Stuckey had access to his farm.
Mrs Stuckey told the Weekend Herald that Mr Lovelock and Detective Senior Sergeant Gary Lendrum arrived at her Pukekawa house on Tuesday, August 20.
She was shocked enough to see them at the door, but said their comments once inside the house were beyond belief.
Mrs Stuckey said Mr Lovelock looked out at the view of the Waikato from her living room and said, "Oh, you can see where Jeanette Crewe came out of the river from here."
"Then Lendrum said, 'Did you know it's 43 years to the day that Jeanette Crewe's body came out of the river?' It was a horrible thing to say."
Mrs Stuckey said the officers told her they wanted to talk about the Crewemurders.
"We knew they were doing the inquiry so we were happy to let them in, but it wasn't very long until we realised just how pointed their questions were. Without a doubt we felt like we were being interrogated.
Police questioned Mr Stuckey, who was working as a fencer at the time of the murders, about work he may have done on the Crewe farm and suggested he'd argued with Mr Crewe over a job.
They also asked him about access he had to Mr Thomas' farm and firearms.
"They said that the Thomas rifle had not been eliminated from the inquiry, that the Crewes were murdered by Arthur Thomas' gun," Mrs Stuckey said.
"They asked: 'You've been around there looking after the house while Arthur was on holiday, haven't you?"'
Mr Stuckey said: "They said to us more than once that the bulk of the evidence still pointed towards Arthur. They didn't say he was guilty or anything, but they said the evidence still pointed to him.
"What they are trying to do is either bolster up something that goes along with Arthur being convicted, which they can't do because he's had a pardon, or come back to his farm by asking if I had access ... and trying to offload it on to me. That's obvious."
Two days after speaking to him in person, Mr Lendrum phoned Mr Stuckey and asked him for an alibi.
"He asked me where I was on the night of the murder ... He rang back the next day and asked again. I said, 'You listen to me and listen real bloody good. If you carry on this way there will be a harassment charge against you.' That was the finish, that was my answer."
Mrs Stuckey said: "I know exactly where Buster was the night of the murder. I know exactly where we both were. But I don't feel compelled to answer that question.
"Arthur had an alibi. We knew where he was on the night of the murder and look where that got him. It didn't make any difference."
Police also questioned the Stuckeys about their religion.
"They asked me point blank, 'Why did you become a Christian?"' Mrs Stuckey said.
"I know what they were thinking. ... But long before the Crewes were murdered, as a child, I was interested in Jesus. It had nothing to do with the Crewes."
Mr Stuckey adopted his wife's faith after Mr Thomas was jailed.
"The biggest thing to make me change was the Crewe case. There were so many lies and rubbish, I thought there had to be a better way for mankind. We were just so knocked back, there was so much crap. "
Richard Thomas said he was asked about his family, whether he had worked for the Crewes and when Mr Stuckey "became religious".
Police refused to directly answer questions this week about the review.
Acting Assistant Commissioner Glenn Dunbier said speaking to people connected to the case was "a logical and appropriate step in any review of this nature".
"We would be remiss if this wasn't carried out," he said.
"That included approaching members of the Stuckey and Thomas families, who two senior detectives met to discuss matters raised during the review assessment.
"The purpose of the approach was offer them an opportunity to provide further information that could assist police in our assessment of the file."
Mr Dunbier said police considered the meetings with Mr Thomas and his family "courteous and professional throughout".
"As we've said, the purpose of the review, which is being independently assessed by a senior barrister, is to provide a definitive assessment of the evidence gathered in this 43-year-old case using current analytical tools.
"It is also considering allegations against police as part of its scope."
The Stuckeys and Desmond and Richard Thomas feel police are trying to "rattle their cage" to get them to reveal something that will prove one of their family killed the Crewes.
Desmond Thomas said the police continued to deny the findings of the royal commission, and were hellbent on trying to pin the murder on someone connected to his brother in an effort to save face.
He said the review should have been done by an independent body, not the police who were now trying to re-blame the crime on an exonerated man and his innocent family.
"We are sick of the lies, we want someone with an open mind to get in here and clean this thing up."
The Crewe murders
1970: Harvey and Jeanette Crewe are murdered at their Pukekawa farmhouse. Their 18-month-old daughter Rochelle is left in her cot.
1971: Arthur Thomas is convicted of the crime. His supporters protest his innocence.
1973: Thomas is convicted again at a retrial.
1979: Thomas receives a pardon after an investigation ordered by Prime Minister Robert Muldoon.
1980: A royal commission concludes that police planted a shellcase in the Crewe's garden to frame the innocent Thomas for the murder.
2010: Rochelle Crewe asks police to re-open their investigation to find out who killed her parents.
2013: Police re-interview Thomas and other members of his family, asking for alibis.
