Case Study: DNA’s First Case
The November 1983 discovery of a murdered 15-year-old girl in the English village of Narborough ultimately had an enormous impact on international criminal investigation.
Before the four-year murder investigation was completed, a scientific discovery was applied that not only solved a double criminal homicide but also completely revolutionized forensic identification: the mapping of DNA fragments. At first, the murder of Lynda Mann was barely noticed outside the area known as Leicestershire, but it soon launched one of the biggest homicide investigations in English history. A squad of more than 150 detectives was formed and exhausted every lead in the case. So thorough was the investigation that every male between the ages of 13 and 34 living in the area of the murder was noted and, in many cases, questioned. Nonetheless, no murder suspect was apprehended.
Then, in July 1986, 15-year-old Dawn Ashworth, also of Leicestershire, was found brutally raped and strangled. The MO indicated the same killer and alerted authorities to the possibility of a serial killer. This time, more than 200 investigators from across the country were placed on the case. Word of the killings began to be cause for concern in almost all of England, but investigators were still unable to develop significant indicators as to whom the killer might be. At last, a case against one suspect was developed. A 17-year-old hospital kitchen porter linked to the murder through circumstantial evidence was arrested. After interrogation, the suspect admitted to the second killing but denied the first, despite the belief by the police that both victims were murdered by the same person.
The ultimate solution to the problem was found only a short distance away, at Leichester University. Alec J. Jeffreys, a university scientist working in the field of genetic research since the early 1980s, had recently discovered a process of human identification based on the DNA molecule. Whether the suspect’s father or the British police first initiated contact with Jeffreys is still under dispute, but the scientist was well known for his work in a paternity lawsuit in which DNA technology established the identity of the father. In the Narborough murders, Jeffreys analyzed a semen sample from the body of Lynda Mann and then analyzed a sample from the Dawn Ashworth crime scene. The technique yielded a DNA image that was identical for both murders. Then, from the suspect’s blood sample, Jeffreys obtained a comparison DNA fingerprint. Alarmingly, the suspect’s DNA failed to match up with either murder, including the murder to which the suspect had already confessed. The suspect was then released from custody.
Certain of one fact – that the same person had killed both teenagers – investigators decided to single out the perpetrator through genetic fingerprinting. Accordingly, in January 1987, all males 17 to 40 years of age living in the village were asked to submit blood samples. More than 4,500 samples were examined before the police. In September 1987, a local baker, Colin Pitchfork was arrested, and charged him with the murders. Pitchfork had a long history of sexual assault and indecent exposure, and an informant had alerted police that he had cheated on his blood examination by persuading a coworker to submit a blood sample for him. When a legitimate test of the suspect’s blood was conducted, an identical match was made with fingerprints found at both murder scenes. Based solely on DNA fingerprinting and the resulting confession, Pitchfork was convicted of both murders.
Using the context from the excerpt and class material from Chapter 4 and 5, answer the following discussion questions in paragraph form.
The investigation of the Narborough murders introduced criminal investigation to a new era of scientific detection:
- Blood and DNA evidence were used to solve the Narborough murders. Identify how other investigative methods could have possibly been used to solve this crime.
- Identify a recent case in your community or nationally that has been solved using DNA technology?
- During the investigation of more than one murder, should investigators focus on one murder at a time or compare and contrast investigative leads and evidence between murders?
https://www.mediafire.com/file/z0cx50zpyz069kw/CJ+342_Chapter+5.pdf/file
https://www.mediafire.com/file/1cmm5z6vxqkrs5r/CJ+342_Chapter+4.pptx/file
