Role of Forensic Science in trial and investigation

Forensic Science

Forensic science and law

The word Forensic has been derived from the Latin term Forensis which means a public place where the Judicial proceedings are held. Forensics is a branch of study associated with the scientific approach of law and its application in the same. It helps in extracting valuable information and evidence in a criminal case by using scientific methods developed by various scientists of biology, chemistry and medicine.

Forensic Science can be considered as a branch of Law which helps in evaluating various aspects like DNA, fingerprints, samples of blood, test of chemicals and toxins etc. in a trial and investigation of the case.

Forensic experts are appointed in number of cases where it is essential to determine the nature and extent of crime by way of forensics. It is a developing branch of law and is now inculcated within the legal system by way of provisions in the statutes and judicial pronouncements of the Courts in India and abroad.

DNA analysis

DNA stands for Deoxyribo Nucleic Acid. The development of DNA in forensics can be traced back in 1980s when it was used as a method to identify the criminal by way of using blood, semen, saliva or skin cells. It can be considered as one of the most accurate and reliable sources of evidence because of the fact that each and every person has a different DNA. Even a born twin has a difference in their respective DNAs.

Cases of murder, rape, assault and robbery can be easily solved with the use of different forensic techniques including DNA Analysis. Another important benefit of using DNA technology is that it even helps in exonerating those convicts whO have not committed any crime making the legal system sufficiently apt.

NARCO test

NARCO Analysis is basically a test in which, the accused is subject to certain chemicals/drugs and sent into a subconscious state after which, he/she is asked some questions relating to the offence which has been committed.

Although, the consent of the accused plays a vital role so as to whether he wants the NARCO Test to be conducted or not. Since the consciousness of the person is being controlled in these tests, it is upon the will of the person whether he wants to undergo such test or not.

Introduction of the concept in India

In India, various forensic techniques are used in the Criminal Justice system which includes DNA Analysis, NARCO, Brain Mapping, etc. DNA testing has been used in the cases where the question of succession arises in the property matters. If a property is being claimed by many, and the real successor is unknown, DNA Testing is the only way to determine the real owner of that property.

Also, in the cases of Sexual assault, DNA testing proves to be a useful technique as it helps to identify that whether a rape has been committed or not. It also reduces the risk of false reporting of the cases by women.

Similarly, NARCO test proves to be a useful tool to determine the guilt of the accused in case of grave offences or where the evidence is not present in substance.

Provisions in Indian legal system

Indian Evidence Act-

Section-45, talks about the opinion of the experts to be taken by the court in case of determining the handwriting or finger expressions.

Section-46, states that even if a fact is irrelevant otherwise, it can be considered in the court as relevant if supported by the statement of the experts.

Criminal Procedure Code-

Section-293, provides the list of the scientific experts recognized by the government that can help in forming the report in any case to enhance the process of a trial or investigation.

Section-53 and Section-54 also gives the rights to the arrested person to be examined by the medical practitioner who can be also considered as an expert.

The prevention of Terrorism Act-

Section-27, States that the police officer may ask the CJM in writing for obtaining samples of handwriting, finger-prints, foot-prints, photographs, blood, saliva, semen, hair, voice of any accused person, reasonably suspected to be involved in the commission of an offence under this Act.

There are no explicit provisions supporting the Forensic science techniques although, the Supreme Court in its various Judgments has time and again interpreted this concept and clarified the views of the court upon the same.

Landmark Judgments

  • Selvi Vs. State

In this case, it was held by the court that tests such as NARCO should be conducted by the authority only if the consent has been given by the accused person. If such test is conducted without consent, it will violate Article-20(3) of the Constitution of India.

The Supreme Court also laid down certain principles governing how this test must be conducted without violating the basic human rights.

  • Dr. Rajesh Talwar and others vs. CBI, Director

In this case Arushi, a 14-year girl was found to be dead in the home. The report by the parents of the girl in the police station was filed. In this case Hemraj, who was a domestic servant in the house of that family, was suspected of murder of Arushi, but after two days the dead body of Hemraj was also found on the terrace of the house of that family.

The parents of Arushi were arrested by the police. In this case Narcoanalysis test, Polygraph test and Brain mapping test was conducted on the accused person. It was pleaded before the court that the report of these tests cannot be taken as an evidence in the court of law. It was held by the court on behalf of the judgment of Selvi v. State of Karnataka that such tests cannot be conducted by the authority if the consent has not been given by the accused person.

  • Harjinder Kaur vs. State of Punjab and ors.

In this case, the court examined as to what will be the consequences of ordering the blood test in a case.

The DNA testing process had an accuracy rate of 99.99% in order to establish paternity and it is the need of the hour that the police officers should follow scientific investigation including DNA testing, especially in the cases involving crime against women like sexual assault and rape.

“The views of the authors are personal

Frequently Asked Questions

How is Forensic Science used in Criminal Investigation?

Forensic Science techniques can be used at the stage of Trial as well as Investigation. As soon as the person is arrested, the police by taking the permission of the court ask for collection of the evidences and the court can send the same for the expert opinion.

The Narcoanalysis is done by the team which comprise of psychologist and other concerned people along with the police officers.

What is the Admissibility of Narco Tests in courts?

Basically the Narco Tests only aids the investigation procedure in the case and is not admissible as an evidence in India. It can be said that the results of these tests are partially admissible in the court of law because it is the duty of the court to make sure that the personal belief and thinking of the people should not be forcibly brought into the court without consent.

What are the Advantages of Forensic Science?

Various advantages of use of Forensics in Law is as follows-

  1. It helps in determining the identity of a person by use of biometrics.
  2. It helps in establishing the guilt of an accused by identifying fingerprints, footprints, photos, voice analysis etc.
  3. Sex determination is also possible by way of forensics.


My name is Aniket Vashisth and I am a student pursuing Bachelor's in Law from Indraprastha University (Maharaja Agrasen Institute of Management Studies). Being a student of law, I have a keen interest in Researching and exploring new ideas from the existing laws and establish a reasonable interpretation. Currently, I am in 3rd year of my 5-year integrated BALLB Program. My future target is to crack Delhi Judicial Services and become an important part of the Indian legal system in order to inculcate my ideas and serve the Nation. I am an active participant in various National Moot Court Competitions organized across the Country every year.