Kolkata, Sep 28 (IANS): A special court in Kolkata will hear on September 30 Central Bureau of Investigation's plea for narco-analysis of the former controversial principal of R. G. Kar Medical College & Hospital in connection with the rape and murder of a junior doctor within the hospital premises.

On the same day, the special court will also hear CBI's plea seeking a polygraph test of Abhijit Mondal, the former SHO of Tala Police Station, under whose jurisdiction R.G. Kar comes.

Ghosh and Mondal, both in judicial custody, will be presented at the special court on September 30 for a hearing.

The CBI has already conducted a polygraph test of Ghosh in the matter. Now, the Central agency sleuths want his narco-analysis to be done so that its findings can be matched with those of the polygraph test.

There is a basic difference between a polygraph test and narco-analysis. Polygraph test also popularly known as a lie-detector test measures physiological responses like blood pressure, pulse, and respiration of the person being questioned. It is based on the idea that the physiological responses of persons are different when they are lying.

On the other hand, narco-analysis involves injecting the person to be questioned with sodium pentothal, popularly termed "truth drug" or "truth serum", which puts the person concerned in a stage of hypnosis which is believed to make that person speak only the truth.

None of the tests can be conducted without the consent of the person concerned.

On September 25, while rejecting the bail application of Ghosh and Mondal, who were charged with misleading the initial investigation and tampering with the evidence, the special court judge observed that if the charges against them were proven, they could be subjected to capital punishment.