The Hindu : New Delhi News : Law & Order

Online edition of India's National Newspaper
Saturday, Jun 24, 2006

New Delhi

New Delhi

Law & Order

Experts feel that tests like narco-analysis and brain mapping should be conducted only in cases of serious crimes like terrorism and not for offences like drug addiction, says Devesh K. Pandey.

Narco-analysis only for grave crimes: Experts

The Delhi police request for permission to conduct narco-analysis and brain mapping tests on Rahul Mahajan and co-accused Sahil Zaroo in the drug abuse case has once again sparked off a debate on the applicability and effectiveness of such methods of scientific interrogation. Experts feel that the narco-analysis test should be employed sparingly and only in cases of a grave nature like organised crime and terrorism.

In narco-analysis test, the subject is injected with "truth" serum that induces him to give answers voluntarily to specific questions. The serum ensures that his replies are restricted only to the happenings he is aware of. The technology at present is in its nascent stage in the country. It has been found that this method of interrogation is not free from partial contamination, with deception, delusion and fantasy having a role to play. "A normal individual can resist the narco-analysis test," says a senior police officer.

Hence police officers feel that such a technique should be employed only in cases where investigators are pressed for time to dig deep into conspiracies hatched to commit grave offences like terrorist strikes. The police had subjected two of the accused in the October 29, 2005, serial blasts to narco-analysis. Interestingly, according to sources, it somehow did not prove to be of much help.

Another technique of interrogation is the lie-detector test in which the suspect is questioned using various components of the polygraph machine attached to his body. The machine records his blood pressure, pulse rate, respiration and muscle movements during questioning. The set of questions includes several queries whose answers are already known to interrogators. In case of a sudden change in the patterns to a particular question, they conclude that the suspect is lying.

Brain fingerprinting test, known in this country as brain mapping, is another procedure of scientific interrogation. During this test, words and pictures associated with the crime, apart from irrelevant words and pictures, are shown to the suspect on a computer screen. To measure his responses, electrical brain responses are recorded through a headband equipped with various sensors. A specific brain-wave response called a MERMER (Memory and Encoding Related Multifaceted Electroencephalographic Response) is obtained when the brain processes noteworthy information it picks up, confirming that the suspect has information about the crime.

Police officers feel that this technique is instrumental in zeroing in on the culprit. But it also has some shortcomings. Brain mapping determines presence of specific information in the brain, but it cannot tell how it got there. It means that at times it fails to distinguish between the perpetrator of a crime and an eyewitness. It is only when the police have specific information about the conspiracy behind a crime that in no manner would be in the know of any eyewitness that the test can zero in on the perpetrator.

According to experts, it is good that the police have withdrawn their plea for conducting narco-analysis tests on Rahul Mahajan and Sahil Zaroo as the accused have after all not indulged in any heinous crime detrimental to the country's security. The police would be better served if they used this technology more purposefully and judiciously.

Printer friendly page
Send this article to Friends by E-Mail

New Delhi