Introduction:

In 1987 Colin Pitchfork became the first criminal in the world to be convicted by DNA profiling. He was found guilty of two rapes and murders three years apart in Leicestershire, England. The victims, Dawn Ashworth and Linda Mann were both schoolgirls. Police conducted a DNA sweep of the area, but Pitchfork persuaded a friend to take the test for him. Initially he evaded capture, but was caught out when his friend mentioned it in a pub and the police were informed. Pitchfork eventually gave a sample for DNA profiling and this was matched to both offenses. Prior to Pitchfork's arrest the prime suspect, Richard Buckland had been charged with both rapes and murders, even though he had only confessed to one of the murders, but vehemently denied the other. This puzzled the police. They turned to Professor Sir Alec Jeffreys and his then revolutionary technique of Multi-Locus Probe (MLP) DNA profiling to resolve the conundrum. The technique proved that Buckland was innocent of all of the offenses, but that they were indeed linked. Buckland was the first person to be eliminated by DNA profiling. It should be remembered that without the crime scene samples being available for testing Jeffreys could not have demonstrated the capabilities of his technique. Professor Jeffreys' discovery revolutionized the fight against crime. DNA profiling would help to convict many criminals. It would also eliminate many more people from police inquiries. DNA profiling would become perhaps the most important weapon in the fight against crime. However, it is important to remember that it is just one of many techniques available to investigators. The increased use of DNA profiling, especially as advances were made in terms of discriminating power and sensitivity, resulted in greater understanding of the need to protect the integrity of crime scenes and samples obtained from them. DNA profiling is not the only technique to require the integrity of crime scenes to be guaranteed. Each and every development in forensic science depends upon meticulous respect for the integrity of the crime scene and careful observation and photographing of that scene before a single sample is collected. This includes establishing environmental conditions – something of vital importance in forensic entomology.

Careful attention must be paid during the collection of samples to prevent contamination of the evidence. It is necessary to scrupulously follow established procedures for collecting, packaging, storing and transportation of samples obtained from crime scenes. Observation of established procedures in such matters not only preserves the quality of the evidence, but can prevent accusations of malpractice. Respect for the integrity of crime scenes and the evidence obtained from them should be a fundamental tenet of any criminal justice system. Not only should there be stringent safeguards governing conduct at crime scenes, but the consequences for failing to meet these standards should be very high. The cases detailed below illustrate not only the problems that arise when crime scenes or samples obtained from them are not accorded the respect they deserve, but what is possible when they are treated with due respect.