One of the keystones of forensic science is DNA testing. DNA (deoxyribonucleic acid) is the genetic material present in every cell. Each individual has a Unique DNA Profile. There are even a few differences between the DNA of identical twins.
A British scientist, Sir Alec Jeffreys, developed DNA profiling in the 1980s. DNA for profiling can be extracted from samples of human cells found at a Crime Scene, including blood, semen, skin, saliva, mucus, perspiration and the roots of hair, and Profiling can even be carried out on old and dried out samples.
The case of Colin Pitchfork was the first murder conviction based on DNA profiling evidence (there was a previous rape conviction based on this type of evidence).
The ExonerationAfter going missing, Lynda Mann, a 15-year-old schoolgirl, was raped and murdered in the grounds of Carlton Hayes psychiatric hospital in Narborough, Leicestershire, in November 1983. Forensic examination of semen sample showed that it was a type found in only 10% of men, and was from someone with type A blood. However, the police did not find a suspect.
In 1986, another 15-year-old schoolgirl, Dawn Ashworth, was similarly sexually assaulted and strangled in the nearby village of Enderby, and semen samples showed the same blood type.
Richard Buckland, a local 17-year-old with learning disabilities who worked at Carlton Hayes psychiatric hospital, had been spotted near Dawn Ashworth’s murder scene and knew unreleased details about the body. In 1986, he confessed to Dawn Ashworth’s murder but not Lynda Mann’s.
Using Sir Alec Jeffreys’ new technique, scientists compared the semen samples with a blood sample from Richard Buckland. This proved that both girls were murdered by the same man, and also proved that this man was not Richard Buckland – the first person to be exonerated using DNA. . . Read More