Do lie detector' tests pass legal scrutiny?

In high profile criminal cases, the haste to ferret out the truth often triggers demands for a polygraph, or in common parlance, a ‘lie detector’ test. Whether it’s a polygraph or narco-analysis or brain electrical activation profile, there are fundamental rights at play.  Article 20(3) of the Constitution states that “no person accused of any offence shall be compelled to be a witness against himself.” Article 21 guarantees “protection of life and personal liberty except according to procedure established by law.” Do these tests amount to self incrimination? Are they a reasonable restriction on personal liberty? Do they fall foul of constitutional safeguards?

Are these investigative techniques of a testimonial nature if mere inferences are drawn from the physiological responses of the subject with no direct reliance placed on verbal responses? For instance, simple ‘Yes’ or ‘No’ answers may be sought but the results are based on the measurement of changes in several physiological characteristics rather than verbal responses. In brain mapping, there may be no verbal responses at all and inferences are drawn from the measurement of electrical activity in the brain.

After grappling with these questions, the Supreme Court, in a landmark judgment in Selvi Vs state of Karnataka held that “no individual should be forcibly subjected to any of the techniques in question. Doing so would amount to an unwarranted intrusion into personal liberty. However, we do leave room for the voluntary administration of the impugned techniques in the context of criminal justice, provided that certain safeguards are in place. Even when the subject has given consent to undergo any of these tests, the test results by themselves cannot be admitted as evidence because the subject does not exercise conscious control over the responses during the administration of the test. However, any information or material that is subsequently discovered with the help of voluntary administered test results can be admitted, in accordance with Section 27 of the Evidence Act,1872.”

The apex court referred to eight guidelines issued by the National Human Rights Commission on the administration of a polygraph test on an accused in the year 2000. These include consent of the accused, recorded before a magistrate, represented by a lawyer, the test performed by an independent agency in the presence of a lawyer, a clear communication to the accused that the findings would not be a confessional statement but have the status of a statement made to the police, a complete record of the medical and factual narration of the manner of the information received.

These guidelines flow from the doctrine of ‘fruits of a poisonous tree’ that find expression in the Evidence Act, Section 24 of  which frowns upon any confession caused by inducement, threat or promise from a person in authority.

Sections 25 and 26 deal with the inadmissible nature of confessions made to a police officer or while in police custody. The Supreme Court in M.P.Sharma Vs Satish Chandra had clarified that “the phrase used inArticle 20(3) is ‘to be a witness’ and not to ‘appear as a witness.’ It follows that the protection afforded to an accused in so far as it is related to the phrase ‘to be a witness’ is not merely in respect of testimonial compulsion in the court room but may well extend to compelled testimony previously obtained from him.”

The contours of testimonial compulsion were lucidly explained by the Supreme Court in Nandini Satpathy Vs P.L. Dani. Referring to the possibility of flawed police processes as “mischief in the womb”, the court observed that “if the police can interrogate to the point of self - accusation, the subsequent exclusion of that evidence at the trial hardly helps because the harm has already been done.”

 In light of the ‘theory of confirmation by subsequent facts’ incorporated in Section 27 of the Evidence Act, the Court further held that “the police will prove through other evidence what they have procured through forced confession. Both precedent procurement and subsequent exhibition of self-incriminating testimony are obviated by intelligent constitutional anticipation.”

The right against self-incrimination finds recognition in international law. Article 14(3) of the International Covenant on Civil and Political Rights stipulates that no one can be compelled to testify against himself. Article 6(1) of the European Convention for the Protection of Human Rights and Fundamental Freedoms provides for a fair trial and Article 6(2) lays down the presumption of innocence until guilt is proved.

‘Presumption of innocence’ has a direct nexus with the right against self-incrimination as coercing a person to testify would shift the burden of proof of innocence on the accused instead of the prosecution making its case of guilt.

There is also the right to silence of an accused person. Under Section 161(2) of the Code of Criminal Procedure (CrPc), when a person is being examined by a police officer, he is not bound to answer such questions that may expose him to a criminal charge. Moreover, under Section 313(3) of the CrPc, during a criminal trial, a person cannot be punished for refusing to answer questions, or for that matter, even giving false replies!

 As Constitutional guarantees are supreme, the right against self-incrimination, by the latest investigation techniques, is in harmony with the right to a fair trial.

The writer is an advocate at the Madras high court, columnist & author