The Legal Truth about the Lie Detector

Authored by: Aarti Aggarwal

Secret service agents, law officers and espionage recruits have the most fascinating toolboxes (Yes, that’s my love for movies talking). Their occupations center on discovering "the truth" (or a convincing substitute at least) in environments where truth is patchy. So they make use of methods, which attempt to coerce or scare the truth out of those who may possess it. One of the most common interrogation tools in the history of the trade has been the lie detector. Over the years, these machines have helped put people in prison, destroy careers, and possibly even end lives! They are now better known in the industry as the ‘polygraph test’. But can these ‘machines’ actually be used legally in India? Let’s find out…

A quick detour: The science behind the polygraph - When a subject is lying in response to a question, he/she will produce physiological responses that are different from those that arise in the normal course. During the polygraph examination, several instruments are attached to the subject for measuring and recording such physiological responses. The examiner then reads the results, analyzes them and proceeds to gauge the credibility of the subject’s answers.

Coming back to the law, in India any police officer making an investigation may examine you orally if you are supposedly acquainted with the facts and circumstances of a case. And you are under an obligation to say nothing but the truth (Section 161 of the Criminal Procedure Code, 1973). The word truly makes it clear that this obligation comes with legal consequences, i.e. liability to punishment under Section 193, Indian Penal Code, 1860 if truth is not spoken or to punishment under Section 179, Indian Penal Code, 1860 for refusal to answer questions!

But you as an accused will also have the right to refuse to answer any question that may lead to incrimination. At the trial stage, Section 313(3) of the Code of Criminal Procedure, 1973 places a crucial limitation on the power of the court to put questions to you and so does the Indian Constitution with Article 20(3). So what remains of such constitutional guarantees when you have devices such as the lie detector to nonetheless make a big deal out of every lie, you thus far managed to conceal by remaining mum? (Nobody said you were all liars. But let’s just say you were…)

To that effect, these scientific tests may be employed in two ways, that is, they may directly be used as evidence in Court in a trial or they may be used merely as clues for investigation. Where the tests involve the making of a statement, they may be directly adduced in evidence, provided they do not amount to a confession because proof of a confession before a police officer or in the custody of a police officer is prohibited (Section 25-26 of the Indian Evidence Act, 1872). However, if the statements are merely admissions, they may be adduced in evidence (Section 17 of the Indian Evidence Act, 1872). BUT your statements may be used as proof of the specific knowledge with regard to those facts, information about which has resulted in subsequent discoveries during the course of the investigation (Section 27 of the Indian Evidence Act, 1872).

Also know that the polygraph test is unconstitutional if administered without your consent as far as the Supreme Court is concerned under Article 20(3) [Selvi v. State of Karnataka, (2010) 7 SCC 263] yet the said test can be administered to you with consent, provided all the NHRC guidelines (‘Guidelines for the Administration of Polygraph Test (Lie Detector Test) On An Accused, 2000, (Page58-60) are adhered to i.e. you need to be assisted by a lawyer; your consent needs to be recorded before a Judicial Magistrate and you should be told about the implications of your consent and that the information you thus provide will not be used against you as evidence in Court.

The under lying irony to all this remains that that the information or matter collected with the help of the ‘voluntary’ test can be admitted in court under Section 27 of the Indian Evidence Act with no clear guidelines as to what is 'volunteering' and 'being asked to volunteer.' For instance, you saying, 'I wish to take a lie detector test because I want to clear my name"; and you being told by the police, "If you want to clear your name, take a lie detector test" is not the same. In the first situation the person voluntarily wants to take the test. (It will still have to be examined whether such volunteering was under coercive circumstances or not). In the second situation the police implicitly/explicitly links the taking of the test to your clearance of the charges. But this is nowhere legally or judicially addressed so it remains as a grey area, open to interpretation.

In such a scenario, I think it’s best to know your way around the Evidence Act and the NHRC guidelines so that if there is a mad man trying to strap some wires onto you to ascertain whether or not you really love his daughter, you know your way in or out of that as far as consenting to it is concerned, (to begin with).