Smt Selvi & Ors vs. State of Karnataka

In Supreme Court of India
(2010) 7 SCC 263
Equivalent citations
AIR 2010 SC 1974
State of Karnataka
Date of Judgement
5 May, 2010

(CJI) K.G. Balakrishnan, R.V. Raveendran, J.M Panchal


The criminal appeal relate to the involuntary administration of certain scientific techniques, namely narco analysis, polygraph examination and the brain electrical activation profile (BEAP) test for the purpose of improving investigation efforts in criminal cases. The issue has received attention because of the tussle between the growing need of an efficient investigation and the preservation of individual liberties.


The bone of contention involved in the case is the involuntary administration of the impugned techniques which prompts questions about the protective scope of the ‘right against self incrimination’ under article 20(3) of our constitution.


Appellants contention

  • These scientific techniques are a softer alternative to the widespread use of third degree methods by investigators and so violative of the fundamental right provided under Article 20(3)

Respondent’s Contention

  • Citing the importance of extracting information, they contended that these can help the investigation agencies to prevent criminal activities in the future and in circumstances wherein it becomes difficult to gather evidence through ordinary means.
  • Placed reliance on certain provisions of the Code of Criminal Procedure, 1973 and the Indian Evidence Act, 1872 to refer back to the responsibilities placed on citizens to fully cooperate with investigation agencies.
  • No bodily harm by their application and that the extracted information will be used only for strengthening investigation efforts and will not be admitted as evidence during the trial stage.
  • Will lead to improvements in fact finding during the investigation stage and thereby helping to increase the rate of prosecution as well as the rate of acquittal.
  • That the information extracted through these techniques cannot be equated with testimonial compulsion because the test subject is not required to give verbal answers, thereby falling outside the scope of Article 20(3).


I.  Whether the involuntary administration of the impugned techniques violates the ‘right against self incrimination’ enumerated in article 20(3) of the Constitution?

I-A  Whether the investigative use of the impugned techniques creates a likelihood of incrimination for the subject?

I-B  Whether the results derived from the impugned techniques amount to ‘testimonial compulsion’ thereby attracting the bar of Article 20(3)?

II.   Whether the involuntary administration of the impugned techniques is a reasonable restriction on ‘personal liberty’ as understood in the context of Article 21 of the Constitution?


1. Theory behind usage of these techniques and scientific validity:

i) polygraph test: when a subject is lying in response to a question, he/she will produce physiological responses that are different that arise in the normal course. It measures changes in aspects such as respiration, blood pressure, blood flow, pulse and galvanic skin resistance. The truthfulness or falsity on part of the subject is assessed by relying on the records of these physiological responses. This has several limitations. The measured changes in physiological responses are not necessarily triggered by lying or deception but can be triggered by other factors such as nervousness, anxiety, fear, confusion or other emotions. Also an examiner may not be able to recognize deliberate attempts on the part of subject to manipulate the test results.

ii) narco analysis test: this involves the intravenous administration of a drug that causes the subject to enter into a hypnotic trance as the subject goes in a half conscious state and loses awareness of time and place and become less inhibited. It’s shortcomings are that it does not have an absolute success rate and there is always the possibility that the subject will not reveal any relevant information. Supreme court of canada held that The statements made in a hypnotic state were not voluntary and hence cannot be admitted as evidence.( Horvath vs R)

iii) Brain electrical activation profile also known as P300 Waves test: it is a process of detecting whether an individual is familiar with certain information by way of measuring activity in the brain that is triggered by exposure to selected stimuli. It’s limitation is that the subject may have had prior exposure to the material probes making the overall context of investigation meaningless.

It is argued that their results are not entirely reliable since these are essentially confirmatory in nature wherein inferences are drawn from the physiological responses of the subject

In the present case, these tests were conducted at the direction of jurisdictional courts even without taking the consent of the intended test subjects.

It is plausible that investigators could obtain statements from individuals by threatening them with the possibility of administering wither if these tests and so the person being interrogated could possibly make self incriminating statements on account of apprehensions that these techniques will extract the truth. This is more likely to occur when the subject is unaware about his legal rights or is intimidated. A statement obtained through coercion, three or inducement is involuntary and hence inadmissible as evidence during trial. What is to be seen is whether statement made on account of apprehensions of being forcibly subjected to the impugned tests will be involuntary and hence inadmissible.

2. Rationale behind the right against self incrimination: Article 20(3) says No person accused of any offence shall be compelled to be a witness against himself. This is a human article, a guarantee of dignity and integrity and of inviolability of the person and refusal to convert an adversary system into an inquisitorial scheme in the antagonistic ante chamber of a police station. this right is viewed as an essential safeguard in criminal procedure. It’s underlying rationale broadly corresponds with two objectives- firstly that of ensuring reliability of the statements made by an accused and secondly ensuring that such statements are made voluntarily as the person suspected or accused of a crime may have been forced and compelled to testify through methods involving coercion, threats or inducements during the investigative stage. When a person is compelled to testify there is a higher likelihood of such testimony being false. False testimony is undesirable since it impedes the integrity of the trial and the subsequent verdict. Therefore the purpose of the rule against involuntary confessions is to ensure that the testimony considered during trial is reliable. The premise is that involuntary statements are more likely to mislead the judge and the prosecutor, thereby resulting in a miscarriage of justice. This delay by giving false statements can also be caused during the investigative stage. This right is a vital safeguard against torture and other third degree methods that could be used to elicit information. It’s serves as a check on police behavior during the course of investigation. Compelled testimony should be excluded as otherwise the investigator’s inclination will be more towards extracting information through such compulsion as a matter of course and will lead to frequent reliance on such short cuts thus compromising the diligence required for conducting meaningful investigations.

The interrelationship between right against self incrimination and the right to a fair trial has been recognized in most jurisdiction as well as international human rights instruments. For eg : US Constitution incorporates the privilege against self incrimination in it’s fifth amendment and this has been interrelated with other constitutional rights such as protection against unreasonable search and seizure and the guarantee of due process of law.

In the Indian context Article 20 (3) should be construed with due regard for the interrelationship between rights since this approach was recognized in Maneka Gandhi’s case. Hence this right is to be examined in respect of its relationship with the multi dimensions of personal liberty under article 21 which include guarantees such as the right to a fair trial and substantive due process. Also Article 20 and 21 have a non derogable status within part III of our Constitution because the Constitution (44th amendment act, 1978) mandated that the right to move any court for the enforcement of these rights cannot be suspended even during the Operation of a proclamation of emergency.

There have been many constitutional protections being given to accused persons. For instance section 161(2) Crpc prescribes that when a person is being examined by a police officer, he is not bound to answer such questions, the answers of which would have a tendency to expose him to a criminal charge or a penalty or forfeiture and he can choose silence in response to questioning by a police officer during the stage of investigation.

Not only does an accused person has the right to refuse to answer any question that may lead to incrimination’, there is also a rule against adverse inferences being drawn from the fact of his/her silence.

Section 313(3) Crpc places a crucial limitation on the power of the court to put questions to the accused so that the latter may explain any circumstances  appearing in the evidence against him.

Proviso to section 315(1) of Crpc mandates that even though an accused person can be a competent witness for the defence, if he/she fails to give evidence, that failure cannot be brought into use in any of the comment by any of the parties or the court or in any presumptions against himself or any person charged together with him at the trial.

The rationale behind all of this is that any civilized system of criminal jurisprudence must accord to the judiciary some means of excluding confessions or admissions obtained by improper methods. This is not only because of the potential unreliability of such statements but also and perhaps mainly because in a civilized society it is vital that persons in custody or charged with offences should not be subjected to ill treatment or improper pressure in order to extract confessions.

I-A To answer the first issue let us first deal with the sub issues

a. First we should see whether the scope of the right against self incrimination extends to the investigative stage or confined to the trial stage?

For this the court placed reliance on M.P Sharma V Satish Chandra, State of Bombay vs Kathi kallu and Nandini satpathy vs PL Dani and held that protection afforded to an accused insofar as it is related to the phrase ‘to be a witness’ is not merely in respect of testimonial compulsion in the courtroom but may well extend to compelled testimony previously obtained from him. It is available therefore to a person against whom a formal accusation relating to the commission of an offence has been levelled which in the normal course may result in prosecution. Also, had it been confined to the courtroom, the whole purpose would have been defeated as the subject could be compelled to give all the evidence outside court and then having it proved by other witnesses.

b. Who is an accused for the purpose of Article 20(3)?

The protection contemplated  by section 161(2) Crpc read with section 161(1) protects any person supposed to be acquainted with the facts and circumstances of the case in the course of examination by the police. Therefore the right against self incrimination’ protects persons who have been formally accused as well as those who are examined as suspects in criminal cases. It also extends to cover witnesses who apprehend that their answers could expose them to criminal charges in the ongoing investigation or even in cases other than the one being investigated. Covers not merely accusations already registered in police station but those which are likely to be the basis for exposing a person to a criminal charge.

c) What constitutes incrimination?

The scenario under consideration is one where a person in custody is compelled to reveal information which aids the investigation efforts. The information so revealed can prove to be incriminatory in the following ways:

i) The statements directly relief upon

ii) Derivative use: information leads to the discovery of independent materials thereby furnishing a link in the chain of evidence

iii) Transactional use: information received helpful in other case

iv) Extracting material to compare with already gathered material for eg: handwriting

I-B Whether the test results are of a testimonial nature, thereby attracting the protection of Article 20(3)? The phrase that has been used in article 20(3) is ‘to be a witness’. This phrase is not confined to oral testimony and that it includes certain non verbal forms of conduct such as the production of documents and the making of intelligible gestures

It was held in Kathi Kallu oghad that ‘to be a witness’ may be equivalent to furnishing evidence in the sense of making oral and written statements but not to be extended to include giving of thumb impression or impression of palm or foot or fingers or specimen writing or exposing a part of the body by an accused person for the purpose of identification. For this, it is necessary to distinguish testimonial compulsion from collection of physical evidence. For eg even though acts such as compulsorily obtaining specimen signatures and handwriting samples are testimonial in nature, they are not incriminating by themselves if they are used for the purpose of identification and corroboration. The relevant consideration for extending the protection of 20(3) is whether the materials are likely to lead to incrimination by themselves or furnish a link in the chain of evidence.

Self incrimination’ can be defined as the information that has been conveyed is based upon the personal knowledge of the person giving the information and cannot include merely the mechanical process of producing documents in court. The provisions of the constitution which prohibits the compulsion must be of such a character that by itself it should have the tendency of incriminating the accused.

An important statutory development in our legal system was the introduction of provisions for medical examination with the overhauling of the Crpc 1973. Section 53 & 54 of the Crpc (recommended by the 37th and 41st law commission reports) contemplate the medical examination of a person who has been arrested either at the instance of the investigating officer or even the arrested person himself or at the direction of jurisdictional court. Section 53 contemplates the use of force as is reasonably necessary for conducting a medical examination. Also explanation to this section should be read so as to confine its meaning to include only those tests which involve the examination of physical evidence and does not include forms of medical examination that include testimonial acts. The results of the impugned tests are testimonial acts for the purpose of invoking the right against self incrimination’. There has been a deliberate and rational distinction between the examination of physical substances such as blood tests and testimonial acts.

Narco Analysis technique clearly involves a testimonial act. A subject is encouraged to speak in a drug induced state and there is no reason why this should be treated any differently from verbal answers during an ordinary interrogation.

In the case of polygraph and BEAP test it often asserted that since inferences are drawn from the physiological responses of the subject and no direct reliance is placed on verbal responses, it will not come under oral testimony.

The difficulty arises since the majority opinion in the case appears to confine the understanding of personal testimony to the conveyance of personal knowledge through oral statements or statements in writing. But the court held that even though the actual process of undergoing these tests is not the same as that of making an oral or written statement but the consequences are similar as by making inferences from their results the examiner is able to derive knowledge from the subject’s mind which otherwise would not have become available to the investigators. The measurement of the physiological responses become the basis of transmission of knowledge.

The results obtained from the impugned techniques are treated as personal testimony since they are a means of imparting personal knowledge about relevant facts. Hence their involuntary administration come within the scope of testimonial compulsion thereby attracting the protective shield of Article 20(3).

And therefore court answered the first issue in affirmation that the involuntary use of the said techniques are definitely violating the right against self incrimination’ provided under Article 20(3).

II. Dealing with the second issue:

Article 21 says no person shall be deprived of his life and liberty except according to procedures established by law. Guarantee of ‘substantive due process’ is a part and parcel of the idea of personal liberty protected by article 21 of the Constitution. This right is a freedom from restrictions or encroachments whether directly imposed or indirectly brought about by calculated measures.

 Let us deal point wise:

a. Whether these techniques can be read as to entail physical confinement of the subject?

The following points will lead to the inference:

i) Use of physical force to ensure that an unwilling person is confined to the premises where the tests are to be conducted

ii) Drug induced revelations or the substantive inferences drawn from the measurement of the subjects physiological responses can be described as an intrusion into his mental privacy

iii) A person could make an incriminating statement on being threatened with the prospecting administration of these techniques

The restrictions placed on the personal liberty need to be evaluated on the basis of criteria such as fairness non arbitrary and reasonableness and cannot be granted in the absolute sense. Also subjecting a person to the impugned techniques in an involuntary manner violates the prescribed boundaries of privacy which can be read under article 21 as part of personal liberty.

b) Right against cruel inhuman and degrading treatment

Even though this right cannot be asserted in an absolute sense there is a sufficient basis to show that article 21 can be invoked to protect the bodily integrity and dignity of persons who are in custodial environments. This protection extends not only to convicts and trials but also to persons who are arrested or detained in the course of investigations in criminal cases. Judgements such as DK Basu vs state of West Bengal have stressed upon the importance of preventing cruel, inhuman or degrading treatment of any person taken into custody. In our case any person who is forcibly subjected to the impugned tests in the environs of a forensic laboratory or a hospital would be effectively in a custodial environment for the same. The presumption of the person being in a custodial environment will apply irrespective of whether he/she has been formally accused or is a suspect or a witness. Even is there is no overbearing police presence the fact of physical confinement and the involuntary administration of the tests is sufficient to constitute a custodial environment for the purpose of attracting article 20(3) and 21.

c) Right to a fair trial

Access to legal advice is one the most essential component of a fair trial but even the best of legal advice can prove to be ineffective as it cannot prevent the extraction of information which may prove to be inculpatory by itself or lead to the subsequent discovery of incriminating materials.

Another component is that at the stage of trial the prosecution is obliged to supply copies of all incriminating materials to the defendant but reliance on the impugned techniques could curtail the opportunity  of presenting a meaningful and wholesome defence

Even though India does not have a jury system, the use of the impugned techniques impedes the fact finding role of a trial judge since the same judge presides over the evidentiary phase of the trial as well as guilt phase. The consideration of test results could prejudice judge’s mind.

Examining the compelling public interest: Respondents have argued that even if compulsory administration of these techniques amounts to intrusion into personal liberty, their investigative use is justifiable since there is a compelling public interest in eliciting information that could help on preventing criminal activities. Court held that it the task of legislature to arrive at a pragmatic balance between the often competing interests of personal liberty and public safety . Courts can only seek to preserve the balance between these competing interests as reflected in the text of the constitution and its subsequent interpretation. The rights guaranteed in article 20 and 21 have been given a non derogable status and they are available to citizens as well as foreigners. It is not within the competence of the judiciary to create exceptions and limitations on the availability of these rights.

Answering the second issue court said that the involuntary administration of these techniques do not amount to reasonable restriction on Article 21.

The national human rights commission had published guidelines for the administration of polygraph test on an accused in 2000:

a. There should be no administration of lie detector tests except on the basis of consent of the accused.

b. If the accused consents, he should be given access to a lawyer and the physical emotional and legal implications of such tests should be explained to him.

c. Consent should be recorded before a judicial magistrate

d. The person alleged to have agreed should be legally represented during the hearing before the magistrate.

e. At the hearing, accused must be told that the statement will have the status of statement made to the police and not a confessional statement

f. Magistrate shall consider all factors including length of detention and nature of interrogation

g. The actual recording of test shall be done by an independent agency and conducted in the presence of a lawyer

h. The medical and factual narration of the manner of information received must be full recorded.


1. The compulsory application of these impugned techniques is a violation of the right against self incrimination as the rationale behind the right is to ensure the reliability and voluntariness of statements that are admitted as evidence. This court has recognized that the protective scope of Article 20(3) extends to the investigative stage in criminal cases and when read with section 161(2) of Crpc, 1973 it not only protects the accused and suspects but also the witnesses who are examined during an investigation. Compulsion makes the test results inadmissible. The article further provides protection to an individual in choosing whether to remain silent or speak, irrespective of whether the subsequent testimony proves to be inculpatory or exculpatory. It aims to prevent the forcible conveyance of personal knowledge that is relevant to the facts in issue. The administration of these techniques gives the results a testimonial character and they cannot be categorized as material evidence

2. Forcible administration of these techniques also violates the standard of ‘substantive due process’ restraining personal liberty whether applied during the course of an investigation or for any other purpose as it exposes a person to adverse consequences of a non penal nature. The explanation to sections 53,53A and 54 of Crpc which enable medical examination during investigation in criminal cases cannot be so extended to include within it the usage of these impugned techniques.


One of the main functions of  constitutionally prescribed rights is to safeguard the interests of citizens in their interactions with the government. As the guardians of these rights, we will be failing in our duty if we permit any citizen to be forcibly subjected to these tests in question. Some of the parties who will benefit from this decision are hardened criminals who have no regard for societal values but the implications of the decision should not be confined to the facts in hand but extend to the whole population as well as future generations.

Edited by J. Madonna Jephi

Approved & Published – Sakshi Raje

Shivangi Goel
I am Shivangi Goel, currently in my final year of a three year LL.B. programme at Campus Law Centre, Faculty of Law, University of Delhi. I am up for exploring every branch in the field of law but Constitutional, Criminal and Competition laws interest me the most. I have a flair for research, analysis and writing which have been further enhanced by my graduation in Sociology. I am thankful for being provided this opportunity by Law Times Journal to optimally utilize and further work upon my skills. I hope this piece of writing helps you in a quick understanding of the important cases affecting the socio-economic scenario of the country and legal concepts involved.