The Supreme Court of India yesterday delivered a lengthy judgment in the case of Smt. Selvi & Ors. v. State of Karnataka Criminal Appeal No. 1267 of 2004, which, in the words of the Chief Justice, involved a:
batch of criminal appeals [relating] to the involuntary administration of certain scientific techniques, namely narcoanalysis, polygraph examination and the Brain Electrical Activation Profile (BEAP) test for the purpose of improving investigation efforts in criminal cases.
The three-judge bench held that "the compulsory administration the impugned techniques violated the 'right against self-incrimination'" and violated as well "the standard of 'substantive due process' which is required for restraining personal liberty." Deciding that a suspect could voluntarily agree to undergo these techniques, the court added this caveat:
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…
As well, the court set out eight guidelines to be followed if any of the three tests were to be administered to a voluntary suspect.
The impugned tests, described in some detail within the judgment, were:
- Narcoanalysis — The administration of sodium thiopental (aka Pentothol or "truth serum") to remove the suspects inhibition about talking.
- Polygraph examination — The "lie detector" with which we are familiar, thanks to movies and TV
- Brain Electrical Activation Profile (BEAP) test — (aka P300 Waves test) The measurement of brain activity to indicate whether the suspect recognizes a visual or auditory stimulus.
The court considered numerous foreign precedents, including two Supreme Court of Canada judgments, R. v. Béland  2 S.C.R. 398 [admissibility of polygraph evidence] and Horvath v. The Queen  2 S.C.R. 376 [interrogation involving hypnosis].