This analysis delves into the seminal case of Selvi v. State of Karnataka, AIR 2010 SC 1974, which elucidates the scope and limits of Article 20(3) of the Indian Constitution concerning self-incrimination. The Supreme Court's ruling, which mandates that lie detector tests may only be administered with the accused's consent, marks a significant expansion of constitutional protections against involuntary self-incrimination. This analysis further contextualizes the Court's findings within the broader framework established by Nandini Satpathy v. P.L. Dani, AIR 1977 SC 1025, which established that constitutional protections under Article 20(3) extend to police interrogation.

Introduction
Article 20(3) of the Indian Constitution embodies a fundamental safeguard against self-incrimination, ensuring that no individual can be compelled to testify against themselves in a criminal case. This provision reflects the broader principle of fair trial and personal liberty, integral to the rule of law. The case of Selvi v. State of Karnataka (AIR 2010 SC 1974) significantly expanded the interpretation of this constitutional protection by addressing the admissibility of polygraph, narcoanalysis, and brain mapping techniques in criminal investigations. This judgment, alongside the earlier precedent of Nandini Satpathy v. P.L. Dani (AIR 1977 SC 1025), forms a crucial part of the jurisprudence concerning self-incrimination in India.

Case Analysis
Selvi v. State of Karnataka involves the application of lie detector tests-specifically polygraph, narcoanalysis, and brain mapping—to criminal investigations. The accused, in this case, challenged the constitutionality of these methods when administered without their consent, arguing that such practices infringe upon their rights under Article 20(3).

The Supreme Court's Ruling

The Supreme Court, in its judgment, held that:

• Consent Requirement: The Court ruled that administering lie detector tests, including narcoanalysis and brain mapping, constitutes a form of testimonial evidence. Consequently, such tests may only be conducted with the express consent of the accused. This requirement is rooted in the principle that any evidence obtained involuntarily, and thereby potentially self-incriminatory, violates the constitutional safeguard against self-incrimination.
   
• Article 20(3) Application: The Court underscored that Article 20(3) extends protection not only during judicial proceedings but also at pre-trial stages. The fundamental right against self-incrimination necessitates that even during investigative processes, the accused must not be subjected to methods that could coerce self-incriminatory disclosures without consent.

Nandini Satpathy v. P.L. Dani

Nandini Satpathy v. P.L. Dani (AIR 1977 SC 1025) established that the protections under Article 20(3) are applicable from the stage of police interrogation. In this case, the Supreme Court reinforced that the accused's rights under Article 20(3) are engaged not only during formal judicial proceedings but also during preliminary investigations. This judgment set a precedent by affirming that coercive questioning by police officers could infringe upon the right against self-incrimination, thereby requiring safeguards during such interrogations.

Comparative Analysis
Selvi v. State of Karnataka builds upon the foundation laid by Nandini Satpathy v. P.L. Dani by extending the protection against self-incrimination to modern forensic techniques that could potentially elicit involuntary confessions. While Nandini Satpathy addressed traditional methods of interrogation, Selvi deals with advanced scientific methods, underscoring the evolving nature of legal protections in response to technological advancements. The ruling in Selvi reflects a commitment to upholding constitutional safeguards in an era where investigative methods are increasingly sophisticated.

Conclusion
The judgment in Selvi v. State of Karnataka represents a pivotal reinforcement of the constitutional safeguard against self-incrimination, emphasizing the necessity of consent for the use of lie detector tests and similar forensic techniques. By extending the protections articulated in Nandini Satpathy v. P.L. Dani to encompass contemporary investigative methods, the Court has reaffirmed the enduring relevance of Article 20(3) in safeguarding individual rights against coercive practices. This jurisprudence ensures that constitutional protections evolve in tandem with advancements in investigative techniques, maintaining a robust defense of personal liberties.

References:

• Selvi v. State of Karnataka, AIR 2010 SC 1974
• Nandini Satpathy v. P.L. Dani, AIR 1977 SC 1025