[JURIST] India's Supreme Court [official website] on Wednesday struck down [judgment text] the use of so-called "truth drugs" and lie detector tests in criminal investigations. The court held that the involuntary use of narcoanalysis and polygraph tests "amount[s] to an unwarranted intrusion into personal liberty," and that "no individual should be forcibly subjected to any of the techniques in question, whether in the context of investigation in criminal cases or otherwise." The court did leave room for the use of such techniques on a voluntary basis but maintained that certain safeguards should be in place and that "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." The ruling is being hailed by civil rights activists [IANS report], but there is concern about the impact on law enforcement. Narcoanalysis has recently been employed in several high-profile criminal cases [AFP report] including the 2006 murders of 21 people in a New Delhi suburb.

In narcoanalysis, the suspect is injected with drugs such as sodium thiopental, which cause him to be more susceptible to questioning. Evidence obtained through the use of narcoanalysis or polygraphs was previously inadmissible in Indian court under the Evidence Act 1872 [text], but police could use the information to lead to other evidence that might be admissible.