“The analysis can be no better than the sample analysed”
The above quote is The Principle of Analysis, one of the most formidable principles in Forensic Science. These principles lay a guideline and set a standard which ensures the quality of work.
Over the past few decades, the process of investigation by policing agency has been levelled up by the help and support of forensic science. From providing assistance in the collection of evidence to its accurate analysis, all of this has led to the increase in professionalism. The importance of science and technology in policing is now been recognized worldwide.
Crime Scene Investigation is the systemic approach taken to investigate a crime scene. This process involves the use of both scientific and investigative skills. A crime scene investigator is either police officer and/or forensic scientist. The investigator is expected to have experience and expertise skills in creative thinking, application of scientific methods, strong logical reasoning, etc.
When a crime occurs, it is very important to understand its nature and the motive of the criminal. A well-planned investigation leads us to all these answers. The main aim of a crime scene investigation is:
- Recovery of evidence
- Reconstruction of scene of crime
- Determine the modus operandi
- Ascertain the sequence of events that may have led to the incident
Crimes can be solved only when a proper investigation has been conducted. Processing a crime scene involves certain parameters like:
- Secure and isolate the crime scene
- Record the crime scene
- Systematic search for evidence
- Collecting and packaging of evidence
All these above steps involved in Crime Scene Investigation must not be considered dynamically. The most crucial step is proper evidence collection & its documentation because it determines whether any analysis done by forensic scientist will be a success or failure.
From a criminal’s point of view an ideal crime scene will usually be dark, deserted place with minimum surveillance. Such a crime scene may cause it difficult for the investigating team to search efficiently. In such poorly lit crime scenes, the simple visual search may not be sufficient. Thus, to ensure proper evidence collection it is very crucial to use proper lighting.
Depending on the crime scene’s location, the time of day, presence of natural light, etc. different types of lights are used. The mostly common form of light is the visible light. It is generally used to conduct the forensic examination of either the crime scene or the evidence procured from the crime scene.
Many times, it is observed that the stations or control room of the authorities are not very close to the scene of crime. Before leaving for the search, the crime team must ensure that they have all the required things. It is the responsibility of the crime scene investigator to get the details of the location and to interpret which type of light source would be required by the investigating team.
With the developing technology, the criminals have also adapted accordingly. They have started using the help of many newly developed methods which provide them a helping hand in eloping from the eyes of the authorities. This is indeed a nig problem for the investigating agencies. One of the solutions to this problem is the use of Alternative Light Source.
Alternate Light Source (ALS), is an effective, non-invasive, non-destructive, method used for analysing different types of evidence. It helps in revealing hidden evidence and clues which may otherwise prove to be significant.
In general, an Alternate Light Source consists of light source and filter. The light source can be a laser light or an incandescent bulb. ALS may either contain a single filter or a combination of filters. These filters allow only the selected wavelengths of light to pass through them. An ALS may also consist of a device which is used to deliver the light from the source to the area under examination. If the wavelength of…