Hi dear ones,

Here is a branch of science which helps law enforcement agencies in finding the criminals through systematic analysis of the scene of crime.

Forensic science

Forensic science (often shortened to forensics) is the application of a broad spectrum of sciences to answer questions of interest to a legal system. This may be in relation to a crime or a civil action. Besides its relevance to a legal system, more generally forensics encompasses the accepted scholarly or scientific methodology and norms under which the facts regarding an event, or an artifact, or some other physical item (such as a corpse) are ascertained as being the case. In that regard the concept is related to the notion of authentication, where by an interest outside of a legal form exists in determining whether an object is what it purports to be, or is alleged as being.

The word forensic comes from the Latin adjective forensis, meaning “of or before the forum”. In Roman times, a criminal charge meant presenting the case before a group of public individuals in the forum. Both the person accused of the crime and the accuser would give speeches based on their side of the story. The individual with the best argument and delivery would determine the outcome of the case. This origin is the source of the two modern usages of the word forensic – as a form of legal evidence and as a category of public presentation.

In modern use, the term “forensics” in place of “forensic science” can be considered incorrect as the term “forensic” is effectively a synonym for “legal” or “related to courts”. However, the term is now so closely associated with the scientific field that many dictionaries include the meaning that equates the word “forensics” with “forensic science”.

The Importance of Forensic Science in the Criminal Justice System

Forensic science plays an integral role in the criminal justice system. Well-trained forensic scientists and medical examiners can be the determining factor in the ability of evidence to adequately represent the facts of a case. Forensic science can be used in almost any criminal case; however, investigations of homicide, rape, and arson are those that benefit the most from forensic science.

Forensic science has shaped the world of justice, fuelling crime investigations and signifying the progress of modern technology. Forensic science of today covers :

  • Modern computer/clay facial reconstruction;
  • DNA fingerprinting;
  • Autopsy techniques;
  • Forensic anthropology;
  • Toxicology and much more.

What more reliable method is there to prove innocent or guilty other than through science?

Types of Evidence



Biological Evidence

In examining biological evidence, forensic scientists use tools both at the scene, and in the lab. When a forensic scientist arrives at a crime scene, he may look for human remains, blood or other bodily fluids and collect samples of any that are found. Because not all bodily fluids (particularly those that have been cleaned up after) are visible to the naked eye, the scientist can use the chemical Luminol to show latent traces of blood. Where large quantities of blood are present, an expert in blood spatter analysis can examine the patterns and size of the bloody areas to determine information such as the trajectory of the blood. This data can help an investigator deduce what type of weapon was used, or where the perpetrator and victim were standing during the attack.

DNA Evidence

DNA evidence uses the unique genetic markers that identify individuals to determine whether a person was at a scene, or to identify a piece of property as belonging to a specific person. In order to identify an individual’s DNA it must be extracted from a piece of property that a person has had contact with, and has left a bodily fluid such as semen, blood or saliva on. The scientist performs tests that identify genetic markers and create a profile that is unique to that person, and can be compared to a sample taken from any individual. Scientists may also attempt to get enough blood from evidence to conduct toxicology testing, to determine the presence of alcohol, drugs, poisons or chemicals.

Trace Evidence

Trace evidence is found where two objects have made contact with each other. When a person or an object touches another object, some ‘trace’ of the two will be exchanged. This is the theory behind the analysis of fingerprints, tire and footprints, and fiber analysis. Technicians lift fingerprints from surfaces by dusting the area with a powder which sticks to the oils in the fingerprint. She then employs fingerprint lifting tape to take the print from the surface to the lab, where it can be analyzed. In the case of a footprint, tire track or other pattern that was left in an outdoor area, a forensic scientist can fill in the depression with plaster, which can be removed after it sets up. The casting is taken to a lab where it is stored until needed, or compared against a known sample, such as a suspect’s shoe.


Some forensic scientists specialize in the field of ballistics testing. Ballistics is a science that involves the science of the flight path that a bullet takes as it travels to its target. Trained ballistics specialists can glean a tremendous amount of information about the type of weapon that was used, the path of the bullet and more through the examination of the bullet itself. Guns produce a specific pattern of wear and grooves on bullets as they are fired, and this pattern is unique. By examining the bullets and test-firing weapons, an investigator can frequently either identify the type of firearm that was used, where it was fired from, or even match the bullet with a specific weapon.