The prime suspect was Richard Buckland, a local 17-year-old youth, who revealed knowledge of Ashworth’s body, and admitted the crime under questioning, but denied the first murder. Alec Jeffreys, of the University of Leicester, had recently developed DNA profiling along with Peter Gill and Dave Werrett of the Forensic Science Service (FSS) and detailed the technique in a 1985 paper.
I was responsible for developing all of the DNA extraction techniques and demonstrating that it was possible after all to obtain DNA profiles from old stains. The biggest achievement was developing the preferential extraction method to separate sperm from vaginal cells – without this method it would have been difficult to use DNA in rape cases.
Using this technique, Jeffreys compared semen samples from both murders against a blood sample from Buckland which conclusively proved that both girls were killed by the same man, but not Buckland. The police then contacted the FSS to verify Jeffreys’ results and decide which direction to take the investigation. Buckland became the first person to have his innocence established by DNA fingerprinting.
Jeffreys later said:
I have no doubt whatsoever that he would have been found guilty had it not been for DNA evidence. That was a remarkable occurrence.
The Leicestershire Constabulary and the FSS then undertook an investigation in which 5,000 local men were asked to volunteer blood or saliva samples. This took six months, and no matches were found.