Forensic science is a multi-disciplinary subject that applies a broad spectrum of sciences to answer question of interest in legal systems. It uses highly developed technologies in discovering scientific evidences used in the courts of law. This can help in a wide range of situations such as laws or regulations violated for marketing food and drugs, manufacture of medicines, and automobile emissions. However, forensic science is commonly used in crime scene investigations such as robbery, assaults, rape, and murder. A number of sub-disciplines in forensic science are currently being practiced which include criminalistics, forensic economics, forensic entomology, forensic ballistics, and forensic engineering. Forensic scientists work in laboratories, crime scenes, or morgues and they may work for the government, police departments, forensic laboratories, hospitals, and universities.
DNA Profiling is a powerful tool for identification by using the characteristics of DNA. DNA is obtained from a person or a sample of bodily tissue. Human DNA profiles can be used to identify the origin of samples found at a crime scene or for parentage testing.
DNA stands for deoxyribonucleic acid and first observed by the Swiss physician Frederich Meiser. It is a molecule that encodes genetic instructions that circulates in living organisms and other known species that makes us all unique. It is hereditary material to all living organisms as well as in viruses. In human beings, DNA is found inside a special area of the cell called the nucleus and 99.9% of all human DNA are identical; 0.01% is enough to extinguish that we are all unique.
DNA is isolated from the cells and millions of copies are being generated using the ‘Polymerase Chain Reaction’ or PCR Method. By this method, genetic code is produced and being analysed.
Forensic Biology has been used to prove how a crime has been done and by whom it has been committed.
Left behind materials, weapons and traces that establish the identification of the criminal and the victim will be examined thoroughly to ratify a report. Evidences left in the crime scene will be tested using molecular biology or DNA Testing.
Blood stain, cigarette butts, tools or weapons and any other materials left that can be used as evidence will be examined for DNA test. The victims as well as the suspect will also undergo DNA analysis to cross match with the evidences found. With this, truth can be revealed and justice will be served.
Tools are often used by criminals to force entry in premises, open lockers or vaults, and also against victims. They often leave behind evidences for crime scene investigations called tool marks. These tool marks are produced when a tool or an object contacts the surface with sufficient force and creates an indention which permanently reproduce the pattern of the tool or object.
Forensic scientists are able to identify criminals by matching tool marks found in the crime scene with suspected tools. Thus, tool mark examination at the crime scene and laboratory are important.
Any piece of technology that processes information and used in a crime can be referred to as digital evidence.This is the information or data stored on, received, or transmitted in binary form and can be relied on in the court.
Digital evidences are commonly associated with electronic crimes such as child pornography or credit card fraud. These evidences are also often hidden, cross jurisdictional borders, altered or destroyed, and time sensitive. There are different evidence-gathering processes for digital devices depending on the device and different crimes also tend to have one or more digital device used.
Fingerprints can be found on any solid surface including human body. Fingerprints are categorized into three according to the type of surpafces which they are found and if they are visible or not.
- 3D Plastic Prints - Soft Surface
- Visible Prints (Patent Print)
- Invisible Prints (Latent Print)
These prints can be collected using various method like photography, black powder, magnetic powder, etc.
Fingerprint examination involves looking at the quality and quantity of information and compare those collected fingerprints on known prints on file.
The process involves analysis, comparisons, evaluations and verification.
Analysis from the material eveidences gathered from the crime scene or accident scenes. These are evaluated thoroughly to know what may be the cause of the accident, how does it happen and the structural composition of the material that may causes the accident or crime.
Forensic toxicology is the investigation of toxic substances usually handles tests on the presence of gases, alcohol, drugs, metals, and chemicals. It is applied in a wide range of situations such as drug and alcohol tests, sexual assaults involving the use of drugs, and testing of body fluids and tissue samples during autopsies.
Forensic toxicology does not only deal with the presence and amount of toxic substances in post-mortem bodies but also how the body's natural processes affect these substances.
Forensic investigations on fire and explosion involves fundamental principles in fire science theory and fire modelling. It deals with various physical and mechanical processes and mechanisms that leads to the origin of fire and ignition.
Audio and video recordings provide real-time accounts that investigators can hear or watch what is transpired. When high quality audio or video evidence is not available, forensic experts can enhance the recordings and bring out details to provide more audible audio and more clearer picture.
Bloodstain left behind can draw conclusion as to how the blood was shed. These stains may appear at random distribution at crime scenes however, it can be analysed by the spatter patterns, transfers, voids, and other marks in recreating the events that caused the bloodshed.
DNA analysis for semen starts with identifying a stain as seminal fluid though the use of alternative light source like laser. It is important to determine if a sperm cell is present in the stain in order to identify the suspect. Sperm is identified through staining and microscopy.
Hair and fiber are important resources in forensic science and are often responsible in identifying the culprit of a crime. The discovery of hair can determine the race and sex while the fiber can help determine the type of clothing of a person. However, a full detailed microscopical comparison with known sources of hair and fiber should be done prior to DNA analysis. These samples are also usually collected in different containers to avoid cross contamination between the time of collection and analysis.