In a major blow to investigating agencies, the Supreme Court today declared as illegal, the use of narco-analysis, brain-mapping and polygraph tests on suspects. A bench headed by Chief Justice K G Balakrishnan said, no individual can be forced and subjected to such techniques involuntarily, and by doing so it amounts to unwarranted intrusion of personal liberty. It said, forcing an individual to such methods of investigation violates the scheme of legal process.<br/>Even if a person is subjected to such a mode of investigation on consent, the result of the test cannot be an admissible piece of evidence. However, the bench said, if anything obtained by the investigators from such techniques in which a person had volunteered, the agencies can use them for further probe.<br/><br/>The Supreme Court ruling declaring compulsory use of narco-analysis, brain-mapping and polygraph tests on suspects as illegal has received an overwhelming support from legal and constitutional experts. They said that police will no longer be able to misuse them. The experts are also of the view that the verdict is not only in consonance with the spirit of the Constitution but also in conformity with international human rights conventions. Senior advocate K T S Tulsi said, under Constitution, no accused can be compelled to be witness against himself. Agreeing with Tulsi, senior advocate K K Venugopal said such scientific truth-finding tests amount to the testimonial compulsion which is not permitted under the law. Welcoming the judgment, former law Minister Shanti<br/>Bhushan said that it is absolutely correct and it would have no impact on the investigation of criminal cases as these are newly-developed techniques.