Selvi and Ors. v State of Karnataka

Facts

• Investigating agencies in several cases subjected accused persons and suspects to polygraph, narco-analysis, and brain mapping tests without obtaining valid consent
• The validity of compelling such tests, and their use in criminal investigation and trial, was challenged as violative of Art.20(3) and Art.21

Issue

1. Whether the involuntary administration of polygraph, narco-analysis, or brain electrical activation profile tests on an accused or suspect violates Art.20(3) and Art.21 of the Constitution.

Held

• Results from these techniques amount to testimonial compulsion, since they elicit responses from the subject's mind, and therefore fall within Art.20(3) protection
• If administered without free and informed consent, they also violate the right to privacy and mental integrity under Art.21
• These techniques can be administered only with the subject's voluntary consent, given after being informed of all implications, with a lawyer present and the process recorded
• Even with consent, results cannot by themselves be treated as confessions; they may only further investigation, subject to independently corroborated evidence at trial

Ratio Decidendi

Compelling a person to undergo polygraph, narco-analysis, or brain mapping tests without free and informed consent is unconstitutional, violating both the protection against self-incrimination under Art.20(3) and the right to personal liberty and mental privacy under Art.21; even consensual administration does not produce admissible confessions by itself.