“A man has just offered Carol a ride in his car,” a little boy told Mrs. Stephens. Before the alarmed mother could shriek the boy added, “But she refused and ran away.”

Worse was to come, though. Later that day – Tuesday, April 7th, 1959 – another boy saw Carol in a car, which he described as a saloon. The six-year-old girl, who had been sent on an errand by her mother to the corner shop near their home in the Cathays area of Cardiff, was never seen alive again.

Exactly two weeks later, a building surveyor found Carol’s body in a stream at the bottom of a ravine at Llanelly, 60 miles from Cardiff. She was fully clothed and there was no direct evidence of sexual assault. Although she died from suffocation, there were no marks on her body suggesting a struggle or that she was beaten.

More than 10,000 men were interviewed, including 1,000 travelling on business that day. One man was arrested but neither boy picked him out on an identity parade.