In 1983, in England, a 15-year-old girl who was walking home along a country lane near Enderby became the victim of rape and murder. The investigation yielded no suspects. Three years later another young girl was sexually assaulted and murdered in a similar manner in the nearby village of Narborough. Police arrested a teenager named Rodney Buckland, who worked in a local mental hospital. Buckland had made statements incriminating himself in the second murder but proclaiming his innocence in the earlier one.
The police were certain that Buckland had raped and killed both girls. They sent semen samples recovered from the two victims, along with a blood sample from Buckland, to Alec Jeffreys for examination using his new DNA-typing method. The DNA analysis confirmed that the same offender had committed both crimes as police suspected, but it showed that Buckland was excluded. His incriminating statements were false. Thus, Buckland became the first man ever exonerated by DNA typing. Without it he might well have gone to jail for a very long time.
The police then began a massive manhunt for the true perpetrator. They conducted what might be called a “biological evidence dragnet,” or “DNA dragnet.” All the males in the village between the ages of about 14 and 70 were requested to provide reference blood specimens. Most did so—more than 5,000 in all. At this point DNA typing was very new; forensic science laboratories did not even perform it yet. Jeffreys had agreed to do the DNA typing in his lab at the University of Leicester. Because this early form of DNA typing was very complex and time consuming, the Home Office (U.K. government) forensic science lab first “screened” all the specimens using the conventional genetic-marker systems that were discussed earlier in this chapter. This excluded most of the men as potential semen donors on the basis of their ABO blood types, secretor status, and/or isoenzyme types, and they were thus excluded from further consideration as suspects. The remaining specimens were then sent for DNA typing.
In the first round of DNA typing none of the men’s samples matched the types of the semen donor in the crimes. The perpetrator, a 27-year old named Colin Pitchfork, was ultimately found, arrested, and convicted of the offenses, because he had paid someone to give police a voluntary blood specimen using his name. He bragged about this ruse while drinking in a pub, was overheard, and was turned in to the police. The surrogate, when confronted, admitted to the police what he had done. Pitchfork’s DNA types matched those found in the semen recovered from both victims.
