Forensic Science- A World of Law, Crime & Investigation

Forensic Science- A World of Law, Crime & Investigation

Many people have heard the term "forensics" used to describe school debate clubs. There is a similarity between these two forms of the word. In academic forensics, political or other issues are debated between two teams using a logical approach, and likewise in forensic science, the debate (or comparison) is between the physical evidence and the known or suspected circumstances about an event.

Forensics comes from the Latin word ‘forensis’ which means a public discussion i.e. forum.

Forensic Science is the application of science to criminal and civil law. In other words, forensic science is the scientific analysis and documentation of evidence suitable for legal proceedings.



Forensic Science enhances all branches of science and applies to the purposes of the law. Two peculiarities which characterize forensic science are that it is multi-professional and multi-disciplinary.

Multi-professional and multi-disciplinary is given to this field because of its vast nature and it has different areas such as Forensic toxicology, psychology, pathology, podiatry, geology, linguistics, odontology, engineering, DNA analysis, anthropology, optometry, art, botany, archaeology, accounting, digital forensics, criminalistics, trace evidence analysis, ballistics. etc.

Role of Forensic Scientists -

  1. Visits the crime scene, search and collect all the possible pieces of evidence, catalogue the evidences removed and make note of the evidences collected in detail.
  2. After collection, the evidences are analyzed. As part of the analysis, they use all kinds of tools from microscopes to chemicals to computer databases.
  3. Once the analysis is done, the scientists work with law enforcement officials including police officers, detectives, other forensic professionals and describe their findings to them in order to structure their investigation.

After determining the scientific facts from the evidences they evaluated, the Forensic scientists may testify as expert witnesses in civil or criminal courts or other legal proceedings. It is the responsibility of the lawyers, judges, and juries to prosecute, defend, and judge the guilt or innocence of an individual accused of wrongdoing. It is the responsibility of the forensic scientist to present the scientific facts in a fair, objective manner based on accepted scientific methods to facilitate the decision.


  • NEED:
  1. Social Changes- Today’s society is undergoing drastic changes at a very rapid pace. The growing shift from rural to urban society. Use of third-degree techniques in earlier days does not find favour with the new generation of the administrators. etc. These are not completely out but their abuse is increasingly hazardous to criminals.
  1. Anonymity- Quick means of transport and high density of population in cities have facilitated the escape from punishment after commission of a crime. Criminal can hide in the corner of a city or move away thousands of miles in few hours after committing a crime at a particular place and then move to a new place where people from that place will not know who he is and where he has come from.
  1. Technical knowledge- The criminal is using science. Crime techniques are getting refined. The investigating officer needs to use scientific methods to combat the modern scientific criminal.
  1. Wide field- Smuggling, drug trafficking, financial frauds and forgeries offer fertile and ever-expanding fields. International terrorism in recent times has acquired global proportions and gadgetry often utilized by the terrorist in mind-boggling to common investigators. Cyber-crimes have gone beyond earth and in space.


  1. Has a crime been committed?

Consider the case of the recovery of a dead body. The death could be natural, accidental or homicidal. Forensic science gives the foundation of the existence or absence of the facts and circumstances comprising a crime by looking into the nature of death.

  1. How and when was the crime committed?

Examination of corpus deliciti, the evidentiary clues and scene of crime can possibly indicate modus operandi (method of doing something) and the time when it was committed.

  1. Who committed the crime?

Forensic science establishes the identity of culprit through-

  • Personal clues like fingerprints, footprints, blood drops, hair
  • Objects left by him at the scene and with the victim or carried from the scene and from the victim.

It also proves the existence of crime, the perpetrator of crime or connection to crime through-

  • Examination of physical evidence
  • Administration of tests
  • Interpretation of data
  • Clear and concise reporting
  • Truthful testimony of forensic scientists


  1. Law of Individuality-

Every object, natural or man-made has an individuality which is not duplicated in any other object.

Everything from an atom to the environment may it be natural or made by man is unique. Eg- currency notes.

Every currency note having the same value is different because of the different codes. Etc. present for each note.

  1. Law of Exchange-

When two entities come in contact, there is an exchange of traces mutually.’

For example, when a criminal or his instrument of crime come in contact with victim or objects surrounding him, they leave traces (fingerprints, footprints. Etc.) and criminal or his instruments pick up from traces from the same contact in order to complicate the scene for the Forensic scientists.

Sir Edmond Locard initiated this law.

  1. Law of Progressive Change-

Everything changes with passage of time.’

It means nothing is permanent and the rate of change varies tremendously with different object. For example, the scene of crime undergoes rapid change with climate, disturbing the scene by intruders, which later may become unrecognizable if not examined immediately.

  1. Law of Comparison-

Only likes can be compared.’

It emphasizes the necessity of providing like samples and specimen for comparison with questioned sample. For example, if blood found on the scene of a crime is an Rh positive, then it cannot be compared with a person having other blood group but it can be with a person having the same blood group.

  1. Law of Analysis-

Analysis can be no better than sample analyzed.’

This principle states that the samples need to be collected, packed and evaluated in such a way for effective use by the investigating team. For example, blood drops found in two sites at the same scene may not belong to one person.

  1. Law of Probability-

All identifications, definite or indefinite are made, consciously or unconsciously, on the basis of probability.’

It determines chances of occurrence of a particular event in a particular way or fail to take place with equal facility. For example, an unknown man has raped a woman. The corpse has a tattoo scar on its right hand and a healed fracture of the collar bone. The woman with these characteristics is reported missing. What is the probability of the corpse being the missing woman?

(Given the occurrence of tattoo scar on the right hand in the area, 1 in 5000, collar bone fractures 1 in 20,000)

P1 = 1/5000= 2/ (10)4

P2 = 1/20,000= 5/ (10)5

Pt= P1 x P2 = 10/ (10)4 x (10)5 = 1/ 108

Thus, the chances of the corpse being of another woman are 1 in 1,00,000,000.

  1. Law of Circumstantial Evidence/ Facts do not lie-

Facts do not lie, man can and do.’

Oral testimony of the witness is modified by auto-suggestion, external influence, suggestions and opinions of others and rationalization. For example, a person is killed in an accidental firing. Relatives want to implicate their opponents. They procure an unlicensed firearm, fire a cartridge, place it at the scene and plant firearm on the opponent. Police recover the shell and the firearm. Shell is attached to the firearm. Police prosecute the person.

Reference:  CRIMINOLOGY- BR Sharma


Circumstantial Evidence
Expert evidence
Forensics Science
Indian Evidence Act

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