It was a grim sight as the police forensic tent was positioned round the grave in a wintry cemetery in Stonehouse, South Lanarkshire.

There were two bodies to be removed. One was that of an elderly woman.

But the main interest was the second coffin that contained her son, John Irvine McInnes, who had died in 1980.

Glasgow Times:

John Irvine McInnes

In fact, he had taken his own life at the family home in Queen Street, Stonehouse, that year, aged 41.

His remains were to be taken away for forensic examination by pathologists - in particular for traces of DNA.

Positioned nearby were detectives from Partick Police Office in Glasgow.

They had applied for permission to have the body exhumed believing that the man inside was responsible for the death of three women - the man known as Bible John.

The three victims, Patricia Docker, 25, Jemima McDonald, 32, and Helen Puttock, 29, had all been murdered between 1968 and 1969 following a night out at the Barrowland Ballroom in the Gallowgate.

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Helen Puttock

All had been found near their homes in Glasgow after being strangled and sexually assaulted.

Despite one of the most extensive manhunts in Scottish criminal history, their killer has never been found.

In 1995 all three deaths were reviewed by Strathclyde Police including all the original evidence.

A semen stain had been discovered on the tights of the third victim, Ms Puttock, who had been found dead in a back green near her home in Earl Street, Scotstoun.

The detectives were based in the same office used by colleagues 27 years earlier, where all the old files were stored.

Acting on the new information while reassessing the old information, they made a new attempt to identify the killer. 

They came across the name John Irvine McInnes, a former private in the Scots Guards, and furniture salesman in Glasgow.

The name of McInnes was not a new one in the Bible John investigation. 

He had been an early suspect who fitted the description given by a key witness and who was actually at the Barrowland on the night of the murder. 

McInnes was picked up and brought in for questioning within days of the triple murder investigation being launched.

Although he was eliminated from inquiries, some detectives still believed he could be Ms Puttock’s killer.

McInnes had only spent a year in the army, returning to Glasgow where he married and had two children. 

For a while he seems to have led a settled life. 

However, he split up with his wife soon after the birth of the second child, a son. 

Although he came from a family with a religious background, he was also a gambler and a drinker who used to frequent the Barrowland regularly. 

His eventual suicide suggested a man who perhaps had a guilty secret.

On the surface, then, he seemed a possible suspect. But there was a problem. 

On the night of Ms Puttock's murder she and her sister Jean Langford had shared a taxi from the Barrowland with a man who called himself John who peppered his conversation with passages from the bible.

When that information was later made public, the term Bible John was coined.

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A police portrait of Bible John

When McInnes attended an identity parade, Ms Langford simply didn't pick him out.

What is more, she remained convinced that he was not Bible John. 

She was shown photographs of McInnes by police, some doctored to increase his age. 

Ms Langford admitted there was a strong resemblance, but that was all.

The ears were too big and she did not get that shock of recognition. 

There were unfortunately other things that did not quite add up. 

As a married man, McInnes didn't fit the psychological profile of a loner.

None of the clothes in his possession matched the distinctive suit, tie and suede boots which Bible John had worn. 

However, to some detectives, McInnes was still in the frame, and his name stayed on police files as a possible suspect.

Over the years local gossip in Stonehouse had linked him from time to time with the Bible John killings. 

In 1995 the case was reviewed, along with others, when the police began transferring their files onto a computer database. 

The development of DNA tests had given them a new forensic weapon.

One that had simply not been around at the time of the original investigation.

Thankfully Ms Puttock's stockings had been preserved by the original investigators in case fresh evidence ever turned up. 

It yielded a clear enough DNA pattern to suggest McInnes - among others - was worth a second look.

Detectives approached his family and asked if they would agree to tests. They found a close enough match to justify exhuming McInnes's body and taking samples from it to see if there were any similarities.

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On February 1, 1996, they went to the cemetery where he was buried, and reopened his grave, digging into the frozen turf with pneumatic drills and pickaxes. 

Carefully removing the body of his mother Elizabeth who was buried above him, they took away the corpse for detailed examination. 

Two leading pathologists, Professor Anthony Busuttil of Edinburgh University and Dr Marie Cassidy, a consultant attached to Glasgow University, were present as the body was brought to the surface. 

Exhaustive tests were carried out to establish whether this was indeed the man who murdered Ms Puttock. If that could be proved, his links to the other two murders might also be established.

They examined the DNA samples taken from McInnes' thigh bone. They also examined a bite mark found on Ms Puttock’s body.

One problem which emerged almost immediately was McInnes's teeth - or rather his lack of them. 

Ms Langford had spoken of the man having overlapping teeth.

Detectives had hoped that they might be able to carry out dental tests. But when they examined his body, they found that he had been fitted with dentures and they had not managed to trace any dental records. 

More seriously, the DNA tests proved anything but straightforward. There was no immediate match. 

The testing procedure, it seems, was not as clear cut or as conclusive as it was hoped.

After unsuccessful tests in Scotland the samples were sent down to Cambridge for detailed laboratory analysis. 

The scientists, who had previously used DNA in identifying Russian royalty, failed to pinpoint a link. They even consulted experts from the Institute of Forensic Medicine in Berlin.

Five months after the exhumation, the DNA tests proved negative.  

In an unusual step Scotland's top law officer - the Lord Advocate - admitted they had failed to get a match. 

The statement, issued by the Crown Office in Edinburgh, said: "The results of these DNA analyses provide no evidence to suggest that the semen stain or hair left near the body of Helen Puttock originated from John McInnes. 

"The scientist confirmed that the findings excluded McInnes as the source of the stain. 

"The Procurator Fiscal considers that it is reasonable to infer that John Irvine McInnes was not the author of the semen stain." 

Professor Donald MacDonald, the professor of Oral Pathology at Glasgow University, examined the bite mark. 

He said: "The mark on the right wrist of Helen Puttock could be a bite caused by the teeth of John McInnes. 

"Because of the limited detail evident in the bite it is not possible to make a valid judgment about the probability that the mark on Helen Puttock's wrist was a bite made by John McInnes. 

"The odontological evidence does not, therefore, point clearly or convincingly to John Irvine McInnes as being the originator of the bite." 

Even if they had proved a match with McInnes, it might only have proven that he had sex with Ms Puttock, not killed her.

After complaints from McInnes' family, the bodies of McInnes and his mother were reburied.

At the time, Clydesdale Labour MP Jimmy Hood criticised Strathclyde Police for delays in the five-month inquiry and demanded the force make a full apology to the McInnes family. 

He said: "I am absolutely appalled at the way this investigation has been carried out. 

"First we were told that the investigation would take only weeks. 

"Now we are months down the line, only to be told that John McInnes was innocent. 

"The McInnes family have been put under enormous strain by this whole circus." 

To this day the murders of the Patricia Docker, Jemima McDonald and Helen Puttock remain unsolved.

Police Scotland say they are still committed to bringing the man or men responsible to justice.

However, with each passing year that is looking increasingly unlikely.