Selvi vs State of Karnataka, AIR 2010

Quick Summary

• This case deals with the use of scientific tests in criminal investigation: narcoanalysis, polygraph (lie detector) and Brain Electrical Activation Profile (BEAP) or brain-mapping.
• The question was: Can the State force an accused person to undergo these tests?
• The Supreme Court held that involuntary use of these tests violates:
  • Article 20(3) – right against self-incrimination, and
  • Article 21 – right to life and personal liberty, including dignity and privacy.
• Such tests can be done only with free and informed consent, under the supervision of a Judicial Magistrate, and even then the results have limited evidentiary value.
• The judgment tries to balance effective investigation with human rights and sets strong safeguards against abuse.

Issues Before the Court

1. Self-incrimination issue: Does forcing an accused person to undergo narcoanalysis, polygraph or BEAP tests amount to “testimonial compulsion” and violate the right against self-incrimination under Article 20(3)?
2. Liberty and privacy issue: Do these tests, when conducted without consent, violate the right to personal liberty, privacy and dignity under Article 21 of the Constitution?

In simple words, the Court had to decide: Can the State enter a person’s mind through drugs and machines in the name of investigation?

Rules & Legal Principles Applied

• Article 20(3): No person accused of an offence shall be compelled to be a witness against himself.
• Article 21: No person shall be deprived of life or personal liberty except according to a fair, just and reasonable procedure established by law.
• Right to dignity and privacy is part of Article 21. The State must respect bodily integrity and mental privacy.
• Precedents referred:
  • M.P. Sharma v. Satish Chandra – early understanding of self-incrimination.
  • Maneka Gandhi v. Union of India – “procedure” must be fair, just and reasonable.
  • Govind v. State of MP and R. Rajagopal v. State of Tamil Nadu – development of the right to privacy.
• Standard applied: Whether the technique forces the accused to reveal personal knowledge in a way that is against his or her will.

Arguments – Appellant vs Respondent

The Supreme Court gave a detailed judgment and clearly held that involuntary use of narcoanalysis, polygraph and BEAP tests on accused persons, suspects or witnesses is unconstitutional.

• Violation of Article 20(3): Forcing a person to undergo these tests means forcing him to reveal the contents of his own mind. This is a form of testimonial compulsion and is barred by the right against self-incrimination.
• Violation of Article 21: The tests interfere with bodily integrity, mental privacy and dignity. Administering drugs or scanning the brain without consent is not a fair, just or reasonable procedure.
• Scientific limitations: The Court noted that these techniques are not foolproof. The subject may be suggestible, the examiner may be biased, and results can be misinterpreted.
• Evidence value: Any information, statement or result obtained by compulsion through these tests is not admissible as evidence in court.

Practical Directions Issued

• Such tests can be done only with the voluntary and informed consent of the person concerned.
• Consent must be recorded before a Judicial Magistrate, and the person should have access to a lawyer.
• The entire process should be properly documented, preferably with audio-video recording.
• Even when consent is given, the results of the tests are not treated as a confession. At best, they may give investigative leads that must be independently verified.

Ratio Decidendi (Core Legal Rule)

The ratio decidendi of Selvi vs State of Karnataka can be put in simple terms:

If the State forces a person to undergo narcoanalysis, polygraph or BEAP tests, it amounts to making the person reveal the contents of his own mind against his will. This is “testimonial compulsion” and violates Article 20(3). Such involuntary testing also violates Article 21 because it invades bodily integrity, mental privacy and human dignity. Therefore, these tests cannot be administered without free and informed consent, and material obtained by compulsion is inadmissible in evidence.

In short: no one can be forced to “speak through machines” against himself.

Why Selvi Matters Today

• Stronger protection for accused persons: The case reminds police and courts that even in serious crimes, the accused is not just a “data source” but a rights-bearing human being.
• Limits on scientific enthusiasm: It is easy to get excited about technology. Selvi teaches that constitutional values come before gadgets.
• Foundation for privacy law: The reasoning on privacy and dignity helped shape later decisions such as Justice K.S. Puttaswamy v. Union of India, which recognised the right to privacy as a fundamental right.
• Ethical criminal justice system: The judgment emphasises that criminal justice should not become a laboratory of forced experiments. Fairness is as important as catching the guilty.
• Guidance for future technologies: As new tools like AI-based interrogation or neurotechnology appear, Selvi acts as a constitutional compass to check misuse.

For students, this case is a bridge between Criminal Procedure, Evidence and Fundamental Rights.

Mnemonic & 3-Step Memory Hook

Mnemonic: “N-P-B = No Pressure, Boss!”

• N – Narcoanalysis
• P – Polygraph
• B – BEAP (Brain-mapping)

The memory line: “For N-P-B tests, there is No Pressure, Boss – only consent!”
This reminds you that all three tests cannot be forced.

3-Step Hook (for exam answers)

1. Step 1 – Name & Tools: Start with “In Selvi vs State of Karnataka (2010), the Supreme Court examined narcoanalysis, polygraph and BEAP tests.”
2. Step 2 – Articles: Immediately connect them to “These tests were linked with Article 20(3) (self-incrimination) and Article 21 (liberty, privacy, dignity).”
3. Step 3 – Rule: Conclude the core rule: “Involuntary use of these tests is unconstitutional; only voluntary, informed consent with safeguards is allowed, and compelled results are inadmissible.”

IRAC Outline – Selvi vs State of Karnataka

Glossary – Key Terms in Simple English

FAQs – Selvi vs State of Karnataka for Students

Key Takeaways for Exams

• Name + citation: Selvi vs State of Karnataka, AIR 2010 (SC).
• Tests involved: Narcoanalysis, polygraph, BEAP (brain-mapping).
• Key Articles: Article 20(3) (self-incrimination) and Article 21 (liberty, privacy, dignity).
• Rule: No forced N-P-B tests; involuntary use is unconstitutional and results are inadmissible.
• Consent: Tests allowed only with voluntary, informed consent, recorded before a Judicial Magistrate.
• Larger theme: Balancing investigation efficiency with human rights and shaping privacy jurisprudence in India.