Marjorie Gorton, who lives in Lower Heswall and is now 98 years old, was a young WPC of Blackburn Borough Police back in 1948 when this photograph was taken.

Marjorie is the officer on the far right, and was then WPC Whitlock, one of six officers around a table covered in boxes of fingerprints.

The picture is significant because it is a record of an investigation that became a milestone in the history of forensic science.

On May 15 1948, a girl aged just under four was abducted from her cot while a patient at Blackburn's Queen's Park Hospital.

In a crime that shocked the nation, little June Anne Devaney was raped and then killed by being struck repeatedly against a sandstone wall not far from the hospital ward in which she had been sleeping.

Blackburn police immediately called in expert detective help from Scotland Yard. The Borough's Chief Constable requested assistance at 4.20am, and two detectives caught the 6.20am train north from London Euston.

There were some clues. First, a taxi driver reported that he had dropped off a man with a local accent not far from the hospital on the night of the murder.

Second, the killer seemed to have removed his shoes in order to prowl the hospital ward, nevertheless leaving a trail of ten and a half inch footprints made by his stockinged feet.

Third, a bottle containing sterile water had been moved from its trolley and placed by the bedside of June Devaney.

This bottle was covered in several sets of fingerprints.

Everyone with reason to have handled the bottle was fingerprinted - but after this process one set of prints remained unidentified.

At this point it was decided that the fingerprints of every male aged 16 and over who had been in the vicinity of Blackburn on the night of 14-15 May would be gathered and compared to the prints left on the bottle.

Among those whose fingerprints were taken was a 22 year-old ex-serviceman called Peter Griffiths. On August 11, in his home at 31 Birley Street, he willingly co-operated.

The next day, around 3pm, his prints came to be compared to the prints left on the bottle and were found to be a match. On making it, fingerprint expert Colin Campbell is said to have risen to his feet and shouted, "I've got him! It's here!"

By this time officers had taken 46,253 sets of fingerprints, and had fewer than 200 left for comparison.

Peter Griffiths was arrested that evening as he left home to begin a night shift as a packer. At first he denied all allegations but, when confronted with the fingerprint evidence, said: "Well, if they are my fingerprints on the bottle, I'll tell you all about it."

This was the first time in the UK that mass fingerprinting was used to solve a murder.

Peter Griffiths had confessed, but at his two day trial, his defence lawyer, fighting for the young man's life, argued that his client was not guilty of murder by reason of insanity and should therefore be spared the gallows.

The jury was having none of it, and required just 23 minutes to return a guilty verdict.

Peter Griffiths was sentenced to death and hanged at Walton prison in Liverpool on 19 November 1948.

Looking back 73 years Marjorie says: "It was a truly terrible, awful crime, but it also seems terrible that he was hanged. It's hard to imagine the time when we had capital punishment."