What lies beneath

THE Pune Bench of the Bombay High Court granted the Special Investigation Team (SIT) permission to carry out scientific tests on Abdul Karim Telgi, in order to aid investigation and facilitate the collection of evidence. A polygraph test, brain-mapping and a narco-analysis procedure were conducted on Telgi by the Karnataka Forensic Science Laboratory (KFSL) in Bangalore in December 2003.

Polygraph or lie detector test (conducted on December 20): The suspect or perpetrator is hooked to a machine, which records the blood pressure, pulse rate and respiration and muscle movements. The subject is questioned and the reactions are measured. Experts say that when a person lies, he/she perspires. When an uncomfortable subject comes up, the blood pressure may go up. All these reactions are corroborated with other evidence gathered. The polygraph test was among the first scientific tests to be used by interrogators.

P 300 or brain-mapping test (December 21): Sensors are attached to the head and the person is seated before a computer monitor. The subject is then shown certain images or made to hear certain sounds. Combinations of relevant and irrelevant words are shown on the screen. All the while, sensors monitor the electrical activity in the brain and register P300 waves, which are generated only if the subject has some connection with the stimulus, in this case pictures or sounds. In Telgi's case, the brain-mapping test was done in two stages. An interview was conducted before the actual test. Some of the sentences shown to him in order to elicit a response were: `Payment allegedly made to R.S. Sharma', `Threat by Roshan Baig', `Alleged payment of Rs.75 lakh to Dilip Kamath', `Connection with S.M Mushrif in Pune' and so on. According to investigators, he showed signs of recognising the sentence with Sharma's and Kamath's names.

Narco-analysis or `Truth Serum' tests (December 22): Doctors or experts mix a few grams of sodium pentothal or sodium amytal in distilled water. Depending on the person's sex, age, health and physical condition, the mixture is administered intravenously. A wrong dose can sent the subject into a coma, or even result in death. The drug depresses the central nervous system, lowers blood pressure and slows the heart rate, putting the subject into a hypnotic trance. In this state, the subject's imagination is neutralised by making him semi-conscious. Therefore he cannot lie, as he cannot use his imagination. The answers are believed to be restricted to facts that he is aware of or are spontaneous as a semi-conscious person is unable to manipulate the answers.

Sodium pentothal was first used as a `truth drug' during the Second World War. American psychiatrists reportedly used it on soldiers so that they would talk about repressed battlefield experiences resulting in catharsis. At times, it was also used on prisoners of war.

To conduct a narco-analysis test, investigators require permission from the court and the personal consent of the subject. The use of drugs on Telgi in order to extract the truth has created a controversy. Defence lawyers argue that these methods are primitive and no longer in use. Moreover, a narco-analysis test has no evidential value in court.

B.M. Mohan, Director of the KFSL, told Frontline about the procedure: "Sodium pentathol is routinely used in surgery. It is not dangerous when administered by professionals and in Telgi's case every precaution was taken." Mohan said that the rate of administration had been standardised for criminal investigation and that the questions were posed by a clinical psychologist who was part of the investigating team.