However, a statement made by Mr Roddick to the police said Mrs Demler was not the person he saw.
Investigative journalist Bryan Bruce said it took more than a year for police to release the statement to him under the Official Information Act.
He said the statement was given after Mr Roddick had been driven to the Demler farm to see Mrs Demler on June 1, 1972 by Detective Inspector Bruce Hutton, who was heading the inquiry.
During that visit, Mr Roddick said Mrs Demler had darker hair than the woman he had seen, but a second view of Mrs Demler, wearing different clothes convinced him she was not the same woman.
"The statement must be a true one because it was listed as Exhibit R14 at Thomas's second trial. It is not like the bullet evidence. Bruce Roddick took the stand at that trial and had his statement been a forgery he could have been asked about it under oath,'' Mr Bruce said.
"But it was never mentioned at the second trial because the Thomas defence team knew they could not point the finger at Mrs Demler because the Crown had Roddick's statement that she was not the woman he saw that day.''
Mr Roddick's statement proved that the rumours that Mrs Demler feed baby Rochelle were wrong, he said.
"... and she deserves an apology from all those who have made her life miserable over the years with their cruel and unfounded speculations.''
Mr Bruce said speculation about Mrs Demler was able to continue for so many years because police did not release the note.
"The time has come for a Judicial Review, preferably by an overseas judge,'' he said.
But police said Mr Bruce was well aware they had committed "significant resources and expertise'' to a review of the Crewe homicides by Detective Superintendent Andy Lovelock.
Assistant Commissioner Allan Boreham said once completed, the review would then be independently assessed.
"We note that, despite several invitations, Mr Bruce has chosen not to assist this process by providing information for consideration as part of the review.
"We know there is a very strong and enduring public interest in this case and we need to make sure we are meticulous in our approach,'' Mr Boreham said.
It was a complex process with the complexity further increased by age of the matter and the amount of information to assess, he said.