"I suspect the police inquiry into the case, due out in coming weeks, may also fudge the truth. Arthur Thomas certainly predicts it will. If this is so, it is a further insult to the integrity of the commissioners and a direct challenge to the solid evidence they had put in front of them that the shell case was planted."
He said the most compelling evidence showed the bullet taken from Harvey Crewe and the shell case it was said to have come from were never manufactured and put together into a .22 round.
That meant it was impossible for the shell casing used to convict Mr Thomas to be connected to the bullet found in Harvey Crewe.
Another of Mr Gordon's sons, Greg, said: "We are very much aware of the reputation [our] father had and we all cringe when that integrity is brought into question."
The case is the subject of a police review after the daughter of the murdered couple, Harvey and Jeannette Crewe, asked Prime Minister John Key to help find her parents' killer.
In an emailed statement, Mr Bush said the comments were directed at Mr Hutton's family and not the wider community.
"At no time did I make specific reference to the royal commission of inquiry. There was no intention to create the perception that I or NZ Police was challenging the findings of the [inquiry] or the integrity of any individual connected with the inquiry."
However, Mr Bush's comments at the funeral made a direct reference to the Crewe case.
"We all know despite the length and depth of Bruce's term with us in the police, in the public eye he is only associated with one case," he said.
"It is a great tragedy and irony that a man of such great character should have been subject to those accusations."
