In any democratic system, the aim of a criminal proceeding is simple: find the truth and punish the guilty. But courts have an equal duty to uphold the law while doing so.
This raises an uncomfortable question: if evidence is gathered illegally, can a court still admit it to secure a conviction?
For decades, Indian courts have refused to follow the American “fruits of the poisonous tree” doctrine, under which illegally obtained evidence is inadmissible [RM Malkani v. State of Maharashtra, (1973)]. The US logic is metaphorical yet clear – if the tree (investigation) is poisonous, fruits (evidence) must be rejected [Nardone v. United States(1939)].
Indian courts have taken the opposite view: a guilty person should not escape merely because the investigation breached legal procedure. In Pooran Mal v. Director of Inspection (1974), the Supreme Court held that so long as evidence is relevant, the manner of its collection is immaterial. It held that the Indian Evidence Act, 1872 does not address whether illegality in gathering evidence affects admissibility and constitutional rights (as they then stood) do not spell out any scope for the exclusionary principle.
It is evident that the Court’s approach was shaped by a legal landscape where privacy was not recognised as a fundamental right. The Court itself acknowledged, however, that a future constitutional framework could compel a re-examination of the exclusionary principle.
In the United States, privacy has been a part of the Fourth Amendment to the Constitution. The US Supreme Court has consistently held that where evidence has been gathered in violation of the Fourth Amendment rights, it is inadmissible [Fremont Weeks v. United states, 1914; German S. Lopez v. United States of America, 1963; Charles Katz v. United States, 1967].
The US Supreme Court has reasoned that privacy protections apply to all, whether accused or not, and that it is the duty of law enforcement to uphold them. Convictions obtained through unlawful searches, seizures or other intrusions into constitutionally protected privacy should find no sanction in the courts. If unauthorised intrusions are allowed to stand, the Fourth Amendment’s guarantee loses all meaning.
No matter how serious the crime, the pursuit of conviction cannot come at the expense of principles forged through years of constitutional struggle. To admit evidence gathered illegally is, in effect, for the judiciary to endorse those unlawful acts – a clear disregard, if not outright defiance, of the Constitution’s prohibitions designed to shield citizens from such abuses.
It was this understanding, rooted in the constitutional spirit and structure of Fourth Amendment rights, that led the United States to adopt the exclusionary principle.
The Indian position in cases like RM Malkani and Pooran Mal was formed in a period when personal liberty and privacy jurisprudence was underdeveloped. Even then, the Law Commission of India, in its 94th Report (1983), criticised the strict approach, noting the expanding reach of Article 21 of the Constitution. It went so far as to recommend amending the Indian Evidence Act, 1872, to confer discretion on courts to exclude illegally obtained evidence if admitting it would bring the administration of justice into disrepute. Strikingly, this recommendation was made when privacy was not even a recognised constitutional right.
The report reflected a prescient understanding that constitutional values are not static, and that the interpretation of Article 21 would inevitably evolve to include facets of dignity, liberty and privacy. This evolution did occur. In Gobind v. State of MP (1975) and R Rajagopal v. State of Tamil Nadu (1994), the Supreme Court cautiously recognised privacy. In PUCL v. UoI (1997), it held that unauthorised phone tapping violates a person’s privacy protected under Article 21; and finally, in Justice KS Puttaswamy v. UoI (2017), the Court affirmed privacy as a fundamental right. As the Court declared, the maxim that 'every man's house is his castle' is no longer a rhetorical flourish but an essential part of our Constitution.
The collection of evidence is undoubtedly a central part of investigation, but established law requires that it be carried out strictly within the framework of the statute. The principle that statutory procedures must be followed is well settled, reaffirmed from Nazir Ahmad v. King Emperor (1936) to OPTO Circuits (India) Ltd v. Axis Bank (2021). With Puttaswamy, which recognised privacy as a fundamental right, this principle has acquired a constitutional dimension. Any illegal or unreasonable intrusion into an individual’s privacy is not merely irregular, but unconstitutional, striking at the heart of Article 21.
The recognition of privacy as a fundamental right means that any intrusion upon it must now meet the test of a procedure established by law. For instance, telephone tapping carried out in violation of section 5(2) of Telegraph Act, 1885 would be unconstitutional. If evidence is gathered through such unlawful means, can courts in good conscience admit it? To do so would risk bringing the administration of justice into disrepute. When unconstitutional acts are overlooked in the courtroom, public faith in the judiciary, which is one of the pillars on which democratic institutions rest, inevitably erodes.
Legally sanctioned and reasonable intrusions into privacy may be justified, but illegal and unreasonable ones cannot be. The time has come for Indian courts to exclude evidence obtained in violation of an accused’s fundamental rights. A recent Madras High Court decision is a welcome step in this direction [P Kishore v. Secretary to Government, 2025]. In a case of illegal wiretapping under the Prevention of Corruption Act, 1988, the Court held that the constitutional guarantee of privacy extends to the mode of investigation. Drawing on American exclusionary jurisprudence, it ruled that evidence obtained through an unlawful intrusion of privacy is inadmissible, signaling a potential shift in Indian law.
Post-Puttaswamy, India’s constitutional framework is no longer meaningfully different from that of the United States in this respect. Privacy under Article 21 now stands parallel to Fourth Amendment protections, and with it comes the opportunity – and perhaps the duty – to adopt the exclusionary principle.
If privacy violations are ignored in the pursuit of convictions, the right itself is hollowed out. A right stripped of meaningful remedies is no right at all. To treat privacy as a privilege without consequence for its breach is to revert to a time when it was little more than an illusion.
Manu Sharma is a Senior Advocate.