Primer on probe systems

NARCO ANALYSIS

It involves administration of a drug, inducing a hypnotic stage. It is believed that in such a state a person is likely to answer questions more truthfully. Experts say drugs do not guarantee that a person speaks the truth.

POLYGRAPH

WHAT THE SC SAYS

The Supreme Court in 2010 declared that narco analysis, brain mapping and polygraph are illegal, but permitted them only with consent and some safeguards. “We hold 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. Doing so would amount to an unwarranted intrusion into personal liberty,” said the SC bench.