Hyderabad, July 9: The Central Bureau of Investigation probing the Satyam
scam may have successfully secured the nod of court to conduct brain
mapping and lie-detection tests on company's former chairman B Ramalinga
Raju, his brother B Rama Raju and former chief financial officer Srinivas
Vadlamani, but the investigation agency is unlikely to elicit any new
information from them.
Even if it secures new information, it will not be admissible in a court of law.
This is because brain mapping and lie-detection or polygraph tests are yet to
be recognised as tools of evidence by Indian courts. Moreover, experts differ
on the scientific aspects and veracity of such forensic tests.
According to experts, these tests will help identify the precise individual, who has perpetrated crime. The tests will differentiate the perpetrator from those who have acquired information from the secondary sources. "Individuals, who have primary
encoded information, will show the characteristic brain responses, which are
indicative of the possession of first hand knowledge of the event," she said.
The Raju brothers will be subjected to both brain mapping and lie-detection
tests. The CBI employed all methods including the carrot and stick policy to
gather information from the accused. Since they turned out to be hard nuts to
crack, the CBI has banked all hopes on these tests.
Brain mapping test works on the principle that the brain stores information
and when subjected to forensic examination will reveal the "guilty
knowledge". It is also known as brain fingerprinting test. Sensors are
attached to the head of the accused, who is made to sit before a computer.
Certain scenes and sounds connected to the incident are played on the
The sensors monitor the electrical activity in the brain. They register a special
signal called P300 waves, which are generated only if the accused has any
link with the photographs or sounds shown or played to him. There will be
no investigation of the accused, as in the case of lie-detection test.
In polygraph or lie-detection test, the subject is put to a lot of questioning by
the investigating officer. The polygraph test involves recording of
physiological responses to the questions posed to the accused. Body
responses including change in blood pressure, breathing and body
temperature will determine whether the accused is telling the truth.
If the CBI fails to secure the desired information from the Satyam scamsters,
it may approach court for narco or truth serum tests, which work on the
premise that a person under the influence of intoxication will speak the truth.
Though courts in India grant permission for such tests, they do not rely on
the reports as concrete evidence. However, such tests have proved handy for
investigators to get more details, which otherwise would be difficult to
"The success of the polygraph test depends on the person who prepares the
questionnaire. If the questions are pertinent, then correct answers can be
generated," said Dr KPC Gandhi, founder-director of Truth Labs.
1. It works on the premise that the brain stores information and the accused leaks out "guilty knowledge" when subjected to the test.
2. The accused is asked to sit before a computer. Sensors are attached to his head. Then pictures and or sounds connected to the incident are screened or played.
3. The electric waves of the brain are mapped against each picture or sound byte.
4. Brain produces a special electric wave called P300 when pictures or sounds are shown or played to a person, if he has the first hand information. If the brain of the accused produces P300 waves, then he or she is said to be connected with the incident.
1. A special equipment called the lie-detector or polygraph is used in this test.
2. Questions are asked to the accused. The answers are recorded.
3. While recording the answers the person's body responses like temperature, sweat and blood pressure are studied. The variation in these body parameters will tell the forensic team whether or not the person is involved.