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Essay, Paragraph or Speech on “Modern Techniques for Crime Detection” Complete Essay, Speech for Class 10, Class 12 and Graduation and other classes.

Modern Techniques for Crime Detection


Narco Analysis, Brain Mapping and Lie Detector Test—The term narco analysis was coined in 1936 for the use of narcotics to induce a state where the subject talk freely and is deprived of his self-control and will power to manipulate his answers. In a narco analysis test the subjects imagination is naturalised and reasoning faculty affected by making him semi-concious. In this state it becomes difficult for him to lie and his answers are restricted to facts he is already aware of. Some of the well known “truth serums” are seconal hyoscine, sodium pentothal and sodium anytal.

In the early 20th century physicians began to employ Scopolamine along with morphine and chroloform to induce a state of waking sleep during child birth, called because scopolamine was known to produce sedation and drowsiness even while a person was awake. In 1922, it occurred to Robert House, a Dallas Texas obstetrician that a similar technique might be employed in the interrogation of suspected criminals and he arranged two prisoners in the Dallas country jail under the scopolamine. Under the drug both men denied the charges on which they were held. When both were tried later the court found that they were not guilty of the crime. His experiment and this conclusion attracted wide attention and the idea of truth drug was thus launched.

Polygraph—A polygraph or lie-detector is a device which measures and records several physiological variables such as blood pressure, heart-beat, respiration and skin conductivity while a series of questions is being asked.

Brain Mapping—There is another method to uncover the truth viz. P 300 test or brain mapping. In this method, sensors are attached to the subjects head and the person is seated before a computer monitor. He is then shown certain images or made to hear certain sounds. The sensors monitor electrical activity in the brain and register P300 waves which are generated only when the subject recognises the sound or picture. The subject is not asked any questions in this test.

Studies have shown that an innocent suspects brain would not have stored or recorded certain information which an actual perpetrators brain have stored. The Forensic Science Laboratory in Bangalore is the first centre in India that conducts the brain mapping.


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