Bible John is believed to have killed three young women, Jemima Macdonald, Patricia Docker and Helen Puttock between 1968 and 1969, after meeting them at the Barrowlands Ballroom in Glasgow.
As part of the biggest murder investigation of its kind in Scotland, an artist's impression was commissioned using the testimony of victim Helen Puttock's sister Jeannie Williams.
Later, the first black and white photofit ever used in a Scots murder hunt was issued, but neither showed the suspect's overlapping front teeth -- a crucial detail recalled by Jeannie.
Despite numerous theories and thousands of men being interviewed, the killer, dubbed Bible John because he quoted from the Old Testament, has never been identified.
Police forensic artist Melissa Dring Little has now produced a new drawing for a two-part documentary, The Hunt for Bible John, which begins on BBC One Scotland Monday, November 22.
It is based on the original picture by Lennox Paterson, registrar of the Glasgow School of Art, but includes the suspect's distinctive teeth.
Dring Little said: "Jeannie, the victim's sister, when she saw the drawing, said 'give that man a medal', it was so closely resembling what she could recall.
"It is important that any detail that the witness recalls, it should be included. What I'm trying to do is make a copy of his drawing, but open the mouth to depict these teeth."
Ms Dring Little, who previously produced sketches in the Madeleine McCann case, added: "Lennox Paterson had not had the advantage of working for the police before, as I have. At the time they were taking a leap in the dark."
Jeannie, who died in 2010, had recalled how a well dressed man named John had asked Helen to dance and the three of them later shared a taxi.
Helen's body was found the following morning in a back court in Scotstoun. There were signs she had put up a fierce struggle before being knocked unconscious and strangled with one of her stockings.
The police described the suspect as a man aged 25-30, with light auburn-reddish hair brushed to the right. He was around 5 ft 10in and had overlapping front teeth and another tooth missing.
Although the oral feature was never shown in images released during the manhunt, it was seen by police as an essential clue.
Detective Superintendent Joe Beattie, who led the investigation, even kept a plastic replica of them.
The original artist’s impression was eye-catching, but without showing the suspect’s teeth, may have resulted in thousands of men being brought for questioning unnecessarily.
Criminologist Professor Judith Rowbotham tells the documentary: "It does in many ways provide a very problematic distraction for the police. I think that one of the biggest problems with the Bible John theory is the reliance on that image."
George Puttock was on leave from the army at the time of his wife Helen's murder, but stayed at home to look after their two young sons.
He tells the documentary: "They say time's a healer but it never does heal. It's still a vivid memory.
“I know how strong she was. I know what a fighter she was. I knew straight away from what Joe Beattie told me that it was a maniac.
"I'm not getting any younger and I would just love to find out the truth and find that somebody was punished for the hurt, the heartache, that they've caused for me and my family."