Science Fair Project Encyclopedia
Colin Pitchfork (born c. 1961) was the first person to be convicted by the process of DNA fingerprinting. Pitchfork murdered and raped two girls in Narborough, Leicestershire in 1983 and 1986 and was convicted in 1988.
In 1983, a 15-year-old schoolgirl Lynda Mann was raped and murdered in the Narborough area. Using forensic science techniques available at the time, a semen sample taken from her body was found to belong to a person with type A blood and an enzyme profile that matched only 10 per cent of males. With no other leads or evidence, the case was left open.
In 1986 Dawn Ashworth, another 15-year-old, was found strangled and sexually assaulted in the same area. The modus operandi matched that of the first attack, and semen samples revealed the same blood type.
The prime suspect was a local boy, Richard Buckland, 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.
The profiles of the murderer and Buckland did not match, and Buckland became the first person to be exonerated by DNA fingerprinting.
Jeffries 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.
Leicestershire Police and the FSS then undertook a project where 5,000 local men were asked to volunteer blood or saliva samples. This took six months, and no matches were found.
Later however, a colleague of a man, Ian Kelly, heard Kelly bragging that he had given a sample whilst masquerading as his friend, Colin Pitchfork. Pitchfork, a local baker, was arrested and a sample was found to match that of the killer. Pitchfork was convicted and sentenced to life imprisonment for the murders in 1988. Since then, DNA fingerprinting has been used to secure many other convictions.
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