In simple words, forensic science is a study which is applied to criminal and civil laws. Our society has become complex, with increasing crime rates in all parts of the world. It is even difficult for the government to regulate the activities of every human being in the country. Law enforcement agencies, with the help of this technology, carry out investigative functions, in order to stem the tide of criminal and felonious activities in the country. Thereby, it ensures the smooth functioning of the government to some extent. Forensic science technology helps to determine the food quality and drugs potency, regulates automobile emissions, utilization of fuel oils, pesticides, etc. Imagine, without its aid, how could these things be effectively monitored?
American Academy of Forensic Science is the world's largest organization that deals with forensic studies. Forensic science is a vast subject that is studied in various other courses such as pathology, anthropology, toxicology, digital and multimedia sciences, behavioral science, engineering science, etc. Criminal investigators apply various principles to detect the criminal involved in the crime. Most of us are familiar with those techniques by the influence of Sir Arthur Conan Doyle's detective books, which depict the forensic investigation methods through the popular fictional character, Sherlock Holmes.
By examining the ink and paper used in the documents, it is possible to find out the time when the document was written. This is done by passing ultraviolet rays, visible or infrared rays, through the document and analyzing the luminescence of the reflected light. Ultraviolet and visible absorption spectroscopy are used in the document analysis. In this spectroscopic analysis, ultraviolet and visible light are allowed to pass through the organic material, and the wavelength and the amount of light absorbed by the organic material is measured. Infrared spectroscopy analyzes the infrared rays absorbed by the document material and ink used in the document. Watermarks in the paper and composition of the paper material, mark an important record during the document analysis.
Face Identification Technique
Face identification technique involves the study of video and photographic comparison of the suspect, skull-photo superimposition, facial restoration and face reconstruction. The picture of the skull is sketched either on paper or on a computer and this will give the two dimensional view of the skull. Facial tissues are overlaid on the skull and the outline of the face is obtained. While sketching, the forensic artists consider the factors such as age, sex, wounds, injuries, health conditions before the death of the person, unique features on the face, etc. But the three dimensional method, in facial reconstruction, involves the cost of an artist. Clay-like substance is overlaid on the skull manually, and the outline of the face is obtained through this. By using computerized methods, virtual image of the face can be generated.
The Automated Fingerprint Identification System (AFIS) has all data of fingerprints, which can be compared with the required fingerprint for the person's identification. This technique was made possible because of the fact that, all human beings have a unique pattern of fingerprints. There are different patterns of fingerprints. They are arch, tented arch, ulnar or radial loop, whirl, central pocket loop, double loop composite, etc. The structure and pattern of fingerprints are immutable and are considered as a worthy evidence in criminal investigations. Oblique illumination is used to illuminate the invisible fingerprints on a surface. Lasers, ultraviolet rays, fluorescent lights, etc., are also used to examine the fingerprints on a surface. Superglue fuming, fingerprint powders, small particle reagent, etc., are some of the other techniques that are used in fingerprint analysis.
Analysis of Explosives and Firearms
Gun powder, bullets, barrels, cartridges, etc., of a firearm are examined by the firearm examiners. Fingerprints on firearms mostly don't help because, there is a coating of gun oil on a gun, which makes the fingerprints obscure. The bullet analysis will serve as a good evidence because, the bullet may have tissues, blood, etc., on it. Firearms will have different characteristics and the bullet which is fired from the weapon, will help to find out the features of the gun which fired it. The residues after a gunshot help to determine the range of the firearm. The variety of shotguns, bullets, cartridges, rifles, etc., makes it less difficult to identify the firearm and the person who fired the bullet.
The investigation related to serology is done by analyzing the body fluids and tissues such as blood, semen, vaginal secretions, urine, fecal matter, etc. Serology is very useful especially in sexual assault investigations. Genetic marker determination is classified into classical markers and DNA analysis. The classical markers technique involves the examination of red cell antigens, isozymes, serum, hemoglobin, human leukocyte antigen (HLA), etc. The DNA analysis is classified into Restriction Fragment Length Polymorphism (RFLP) and Polymerase Chain Reaction (PCR), which help in the study of DNA sequence.
Photography and Digital Imaging Enhancement Techniques
The image analysis method includes imaging, image authentication, image processing, person identification, image compression, object recognition, data compression, technical investigations, etc. Some photographs taken during the crime scene or any investigation process, are many times obscure. To resolve this problem, forensic scientists in digital imaging field make use of image enhancement techniques such as pixel enlargement, warp, rotation, roaming, sharpening, contrast stretching, voice reality modeling, etc. To get the clear recorded voice data, digital technique like noise reduction is used.
The speech signals that are transmitted through mobile phones, telephones, etc., are analyzed and recorded in a tape. Then, the electroacoustic signals are decoded and the speaker is identified. These evidences are vulnerable to tampering and even deletion of the tape recordings. So, authenticating the evidence is very important.
Other Important Applications of Forensic Science
- Accident investigations
- Determining alcohol content in blood
- Drugs of abuse
- Mass spectrometry
- Clinical forensic medicines
- Sex determination
- Internet crime detection
- Lie detection
- Modus operandi
- Hair identification
- Voice analysis
- Wood analysis
- Fire investigation
It is a very huge field and it covers most of the important aspects of science. If this technology is not utilized in law, justice would be denied for many. The criminal would happily roam along the streets and the innocent might be punished. Hence, it is a very important and useful technological advancement in the history of scientific revolutions.