Author: Ashwina Venkatramanan, School of Excellence in Law, The Tamil Nadu Dr. Ambedkar Law University, Chennai
TO THE POINT
The increasing reliance on scientific methods like narco analysis and polygraph tests in criminal investigations has triggered renewed legal and ethical debates in India, especially following their use in high-profile cases in 2024. These techniques, although promoted as tools to extract the truth from unwilling suspects, raise serious constitutional concerns. The main issue is whether such methods, if conducted without voluntary and informed consent, amount to testimonial compulsion, violating the right against self-incrimination under Article 20(3) and the right to personal liberty under Article 21. While law enforcement agencies argue these tools aid investigations, the judiciary has consistently emphasized that the ends of justice cannot justify the violation of fundamental rights. This article explores whether these tests are truly voluntary or coercive and if their usage can be constitutionally justified.
ABSTRACT
This article explores the controversial use of narco analysis and polygraph tests in criminal investigations within the Indian legal framework. It examines whether these techniques infringe upon constitutional safeguards such as the right against self-incrimination under Article 20(3) and the right to personal liberty under Article 21 of the Constitution. While such methods are often portrayed as effective tools for crime detection, they raise concerns regarding consent, testimonial compulsion, and scientific validity. The article relies on judicial precedents, NHRC guidelines, and recent case studies from 2024 to assess the legality and ethicality of these practices. Ultimately, it argues for strict regulation and the preservation of individual rights in the face of investigatory innovation.
USE OF LEGAL JARGON
Narco analysis, polygraph tests, and brain mapping fall under the umbrella of forensic psychological techniques used to interrogate suspects in criminal cases. Narco analysis involves administering barbiturates (such as sodium pentothal) to induce a hypnotic state in which the suspect is believed to be more truthful. A polygraph test, often called a lie detector, measures physiological responses like heart rate, respiration, and blood pressure when the subject answers questions. The core legal issue centers around testimonial compulsion, a concept grounded in Article 20(3) of the Indian Constitution, which protects an individual from being forced to testify against themselves. When a person is compelled to undergo these tests, it potentially breaches this protection. Moreover, the right to privacy and mental autonomy, now firmly entrenched within Article 21, are at stake. These tests, if administered involuntarily or without proper consent, compromise the integrity of the criminal justice process, raising questions on due process, procedural fairness, and admissibility of evidence.
THE PROOF
In practice, the administration of narco analysis and polygraph tests in India has sometimes sidestepped key ethical and legal safeguards. Investigative agencies have, on occasion, employed these methods to expedite evidence collection in particularly sensitive or high-profile cases. Although detailed reports from 2024 on specific instances are limited in widely recognized sources, concerns have repeatedly surfaced in legal circles and human rights forums regarding the potential abuse of such techniques. Notably, questions have been raised about whether these tests are administered with proper informed consent, as mandated by protocols set forth by the National Human Rights Commission. These controversies are underscored by the landmark Supreme Court judgment in Selvi v. State of Karnataka (2010), which held that forcibly subjecting suspects to narco analysis or polygraph tests violates the right against self-incrimination under Article 20(3) and impinges on the right to a fair trial under Article 21. This precedent reinforces the need for rigorous adherence to constitutional safeguards in any investigative process involving psychological testing.
The National Human Rights Commission (NHRC) guidelines issued in 1999–2000 and reiterated in subsequent manuals, mandate that no lie detector test, including narco analysis, may be conducted without informed, written consent of the individual, with consent recorded before a Judicial Magistrate, and the subject having legal counsel, being informed of physical, emotional, and legal consequences, and undergoing testing in an independent medical environment supervised by a forensic psychologist; tests administered otherwise are unconstitutional under Articles 20(3) and 21. Scientific studies have also criticized these techniques: a 2024 paper in Frontiers in Health Informatics warns that narco-analysis is prone to false positives, memory distortion, and suggestibility , while a 2011 review in the Indian Journal of Medical Research highlights the lack of scientific standardization and legal admissibility of such tests. These shortcomings, coupled with occasional media leaks of test outcomes, underscore their potential to prejudice trial fairness and undermine constitutional protections.
CASE LAWS
The Supreme Court of India, in SELVI V. STATE OF KARNATAKA (2010), delivered a landmark judgment on this issue. The Court held that forcibly subjecting an individual to narco analysis, polygraph tests, or brain mapping violates Article 20(3) and Article 21 of the Constitution. The Court emphasized that such tests constitute testimonial compulsion, as they extract responses from the accused’s mind, rather than physical attributes like fingerprints or handwriting. Even when consent is given, the results of these tests are not admissible as substantive evidence but may be used for investigative leads under Section 27 of the Indian Evidence Act. The judgment laid down strict procedural guidelines for obtaining consent and emphasized the importance of protecting mental privacy and dignity.
Another important judgment is STATE OF BOMBAY V. KATHI KALU OGHAD (1961), which clarified the scope of Article 20(3). The Court distinguished between physical and testimonial evidence, holding that while physical characteristics like fingerprints are not protected under Article 20(3), any evidence that relies on the application of mental faculties (such as confessions or responses under narco analysis) is protected.
In ROJO GEORGE V. DEPUTY SUPERINTENDENT OF POLICE (2008), the Kerala High Court emphasized that such tests must not be used indiscriminately and reiterated the requirement of voluntary, informed consent. It held that the courts must ensure that there is judicial oversight and a genuine investigative necessity, failing which the procedure would be illegal.
CONCLUSION
While narco analysis and polygraph tests offer investigatory potential, their use must be cautiously balanced against constitutional rights and procedural safeguards. The Indian legal framework anchored in Article 20(3) and Article 21 clearly prioritizes the rights of the individual over the convenience of the police. Judicial pronouncements and NHRC guidelines stress that consent must be informed, voluntary, and legally supervised. Moreover, given the scientific unreliability of these techniques, their use must be limited and exceptional, rather than routine. The State must not be allowed to bypass due process by adopting methods that tread dangerously close to psychological coercion. As science advances, so must our legal consciousness, ensuring justice is neither compromised by delays nor distorted by unethical shortcuts.
FAQS
1. Are narco analysis and polygraph tests legally admissible in Indian courts?
No, the results of these tests are not admissible as substantive evidence. At most, they can lead to the discovery of evidence under Section 27 of the Indian Evidence Act if the subject consented voluntarily.
2. Can an accused be forced to undergo these tests?
No. As per the Selvi v. State of Karnataka judgment, forcing an individual to undergo such tests violates Article 20(3) and Article 21 of the Constitution. Consent must be free, informed, and documented.
3. Are these tests scientifically reliable?
No. Forensic experts and journals have consistently criticized narco analysis and polygraph tests for their high error rates, susceptibility to manipulation, and lack of standardization.
4. What is the NHRC’s stance on this matter?
The NHRC mandates that these tests can only be conducted after obtaining informed written consent, with legal and psychological supervision, and in a controlled medical environment.
5. Is there any law that regulates these techniques in India?
There is no specific legislation yet. The procedure is governed by Supreme Court guidelines, NHRC protocols, and judicial precedents like Selvi v. State of Karnataka.