Forensics: The science of crime

In today's world, forensic science has been largely portrayed by television producers with programmes giving some insights into the subject. Forensic science is portrayed as being science used by police to investigate crimes - but this is only a half-truth.

It is true that the largest employers of forensic scientists in this country are police and agencies whose major workload is carrying out investigations of criminal activity. However, forensic science is also a science that aids the legal system, including the civil courts and public inquiries. The use of forensic science even extends to matters that do not go to court, such as the investigation of fires and accidents on behalf of insurance companies. These cases rarely reach the courtroom, but often involve some form of scientific investigation. Perhaps the most striking feature of forensic science as portrayed on television is the wide range of disciplines involved, both at the scene of the incident and in the laboratory.

Scene of the crime

For many cases, the examination starts at the scene of an incident - and this is a speciality in its own right. If materials are not collected and properly stored, they cannot be examined. The crime-scene officers work for the various police forces, and it is they who identify and collect samples that may assist the investigator. Their work is varied, the next job may be another house-breaking, or it may be a major crime such as a murder or terrorist offence. No matter what, their responsibility is to recognise and collect what is important, and then send it to a laboratory for examination. They even need to ensure that the laboratory staff have sufficient information for them to carry out a suitable analysis.

The laboratory work is mainly an application of the techniques of analytical science. In the chemistry branch, the main analytical tools are various forms of chromatography, mass spectrometry and infrared spectrophotometer. These are used when analysing samples for dyes, such as those occurring on textile fibres, when analysing materials such as petrol which may have been used to start fires, or when testing for the presence of illicit drugs in a variety of sample types. In the biology branch, clearly a considerably amount of work involves molecular biology, since DNA technology has revolutionised forensic biology during the last decade. However, there is much more to forensic biology than the application of molecular biology - for example, a study of blood splash patterns can be important in distinguishing between a villain and a Good Samaritan. Other aspects of forensic science involve less common analytical techniques, such as the use of comparison microscopes to examine tool marks.

If forensic science were restricted to the above, then it would merely be analytical science. However, the distinguishing features of forensic science are its professional aspects. In forensic science, it is very often necessary to 'first find your sample'; searching for suitable samples is an integral part of the job, and with the introduction of ever more sensitive analytical techniques, such samples can be smaller and smaller.

Any one case may involve a wide variety of samples, such as tool marks, paint, glass, textile fibres and blood. Whilst it may be technically possible to analyse all of these samples, it is generally undesirable to do so, since forensic science must be cost-effective as well as generally effective! This means that finding the best selection of samples and analytical techniques for those sources is an important part of the job.

Entry Requirements

The prime entry requirement for a career in forensic science is a good Honours degree, grade 2-1 or better, in a relevant subject such as chemistry, biochemistry or molecular biology. However, such is the diversity of forensic science that graduates with other degrees are also considered - for example, engineers carry out traffic accident investigation.

Regardless of the degree, personal attributes are also important. Interaction with others is crucial, since investigations are team affairs, requiring interaction together with a variety of other disciplines. No matter how sophisticated the science, or how meticulously the work carried out, it is all to no avail if the findings cannot be communicated clearly to the courts. Communications are particularly challenging in forensic science, since the recipients may well have little or no scientific training. All communication is initially in writing, and may well be followed by verbal presentations in the courts.

The most apparent employers are forensic science laboratories operated by police forces and the Home Office Forensic Science Service; and scientific support units operated by police forces to examine incident scenes. However, there is a wide range of other employers working in forensic science - for example, in drug screening laboratories - and some graduates have chosen these alternatives as their career.

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