The application of science to those criminal and civil legislations that are enforced by the police agencies in a criminal justice procedure is known as SCIENTIFIC EVIDENCE.

The expression ‘evidence’ has been defined in Section 3 of the Indian Evidence Act. The word ‘evidence’ signifies that state of being evident. All instruments by which relevant facts are brought before the court are included in the term ‘evidence’.

Section 3 of the Indian Evidence Act, 1872 defines evidence as

“Evidence” means and includes

(1) All statements which the Court permits or requires to be made before it by witnesses, in relation to matters of fact under inquiry; such statements are called oral


(2) All documents including electronic records produced for the inspection of the Court, such statements are called documentary evidence.

SCIENTIFIC EVIDENCE,In general, is established on the understanding that has been formulated by wielding the scientific method. This means that the basis for the evidence has been deduced and tested and is normally accepted within the scientific community. The concept on which the scientific evidence is based has been published in scientific journals and has been subjected to a peer review within the scientific community. Several categories of forensic evidence are often regarded as scientific evidence, like DNA matching, fingerprint identification, and hair/fiber evidence. The strategies used to formulate these types of evidence are generally beyond the spectrum of understanding that judges and juries possess and are therefore generally enlisted as scientific evidence.

The Application of science in law is typically recognized as Forensic Science. The region of its application is considerably broad and detailed. Forensic science is that portion without which the riddle of a criminal investigation is left sketchy. Devoid of forensic science, criminals can never be doomed unless an eyewitness exists. While investigators and law enforcement agents are implicated in the compilation of indications, be it manual or digital, it is forensic science that deals with the estimation of those evidence in order to ascertain facts legitimate in the court of law. This, in a world without the discovery of forensic science, murderers, thieves, drug traffickers, and rapists would be prowling scot-free. The obligations and accountabilities of a forensic scientist in a criminal investigation is significant as it involves the thorough analysis of evidence while ensuring that it is not meddled with. A distinct pool of forensic scientists and forensic means go into the examination of a criminal act.

If scientific strategies are taken into deliberation these are not at all illegal or unlawful. Once recovery is made with the help of scientific tools and techniques, the prosecution can easily demonstrate the close association between the finding of a material object in the commission of an offense. Thus, the use of Narco-analysis polygraph and brain-mapping would extensively encourage examination councils that too in a scientific manner without compelling authorities to take refuge in inhumane treatment.

Narco Analysis

The term Narco analysis is derived from the Greek word “Nark” meaning anesthesia. In the test, the subject is injected with a drug, and his imagination is neutralized while he is semi-conscious. It is difficult for him to lie and these answers are restricted to facts he is already aware of. The Narco analysis test in India is done by a team comprising an anesthesiologist, a psychiatrist, a clinical/ forensic psychologist, an audio-videographer, and aiding nursing staff. The forensic psychologist formulated the report about the disclosures, which will be accompanied by a compact disc of audio-video recordings. In order to verify the strength of the revelations made it is further verified by subjecting the person to polygraph and brain mapping tests.

In India, narco-analysis was first used in 2002 in the Godhra carnage case. It was again in the news in the Telgi stamp paper scam when Abdul Karim Telgi was taken to the test in December 2003. Though in the case of Telgi, an immense amount of information was yielded, doubts were raised about its value as evidence. The Bombay High Court, in a significant verdict in the case of Ramchandra Reddy and Others v State of Maharashtra, upheld the legality of the use of P300 or Brain Mapping and narco analysis test. The court also said that evidence procured under the effect of the narco analysis test is also admissible. However, defense lawyers and human rights activists viewed that the narco analysis test was a very primitive form of investigation and third-degree treatment, and there were legal lapses interrogation with the aid of drugs. Narco analysis is in the limelight in the context of the infamous Nithari village (Noida) serial killings. The two main accused in the Nithari serial killings Mohinder Singh Pandher and Surendra Kohli have undergone narco-analysis tests in Gandhinagar in Gujarat.

There is no law which deals with the admissibility of scientific evidence including the Narco analysis test Still the law is not clear about the admissibility of the Narco analysis. But in some cases, courts allow the above sad test when there are no shreds of evidence except the circumstantial evidence. Thus in rare cases courts allow the test to fill the vacuum in the evidence.

Narcoanalysis test on Abdul Rehman for the identification of terrorist activities – A Gulbarga resident Shami Ahamad Saha alias Abdul Rehman (31) was arrested on 31-3-2006 and was subjected to polygraph, narcoanalysis, and brain mapping tests at Forensic Science Laboratory at Bangalore. He is alleged to be a member of Laskhar-e-Toiyaba.


A process in which selected physiological activities are recorded is known as polygraphy. According to the definition of Webster’s legal dictionary, “a polygraph is a device for measuring certain involuntary bodily responses, such as blood pressure and perspiration, from which an opinion is drawn as to whether or not the person being tested is telling the truth. Also called, to some extent positively, a Lie Detector. The problem with it is that it may yield accurate opinions in many cases, it may make nervous or confused truth-tellers, and there is no way to know exactly which results are accurate and which are not.

Nowadays, the control question (CQ) technique is the most commonly used for the Polygraph test. Control question tests are the second group of detection of deception tests. Control question tests are the most commonly used polygraph test in law enforcement today. The High Court of Gujrat in the case of Abbasbaig Habibbaig Mirza v. State of Gujarat [(2005) 3 GLR 2418] held that “The legality, validity or evidentiary value of the Lie Detector test is again a question which has to be determined at the trial”.

Polygraph test conducted on Mumbai serial killer – One Ravindra Kantrolle, a suspect of serial killing of seven people in South Mumbai in Marine Drive and Azad Maidan Police Station was subjected to scientific tests like polygraph, narcoanalysis and higher version of brain mapping tests [i.e., Brain Electrical Oscillation Signature (BEOS)]. During these tests, he confessed his involvement in the crimes.

Brain Mapping

Brain Mapping is one more valuable scientific tool for the investigation of crimes.

Brain Mapping is also known as Late Positive Complex or P3 or P300. It is a component of averaged brain potentials. In this test, no questions are asked by the accused. He is made to sit in an evoked potential recording machine and is shown objects relating to the crime scene or is made to hear sounds pertaining to the crime site. The sensors from his head pick the event-related potentials in the form of Brain Mapping only if the person has been at the site of crime. The accuracy of Brain Mapping is almost 100%. When the brain recognizes a person or a sound, it produces a precise electric wave which is called P30028. In this test, sensors are attached to the head of the subject and the subject is seated before a computerized monitor. The sensors catch the electrical activity in the brain and record the P300 wave, which is produced only if the subject has some correlation with the pictures shown to him and the sounds which he is made to hear.

Brain fingerprinting is a boon for investigating agencies. In a planned commission of a crime, the physical pieces of evidence may vanish or made to vanish and sometimes it happens that no clue of the criminal acts is found. The investigating agencies have to grope in dark in order to catch a suspect. In such a case, the brain fingerprinting has prevented it from being a boon in that regard. In the commission of a crime, the brain of the preparer is always with him while planning, exciting, and committing the crime. By this technique, it is measured as to whether there is crime-related information stored in the brain of the suspect or not.

Case Laws

The scientific test about age as a result of the epiphysis of the bones is held to be most trustworthy. In Harpal Singh v. the State of H.P. (AIR 1981 SC 361), the age of a girl was in question.

Radiologist after examination of the girl found that she was about 15 years of age and

this was corroborated by an entry in the admission register in the government school

wherein the girl was a student, which was proved by the Headmaster, and by a certified copy of the relevant entry in the birth register.

In the State of Tamil Nadu v. Rajendran,[ (1999) 8 SLC 679] the wife was found dead in a hut which had caught fire. But the medical evidence showed that the wife died due to asphyxia as a result of strangulation and not on account of burn injuries. Later, in trial court came to the conclusion that it was the husband who strangled his wife and thereafter set the hut on fire.

It is important to note that usually with death blood disappears from the heart but the heart in asphyxia, specifically the right chambers are always found full of dark venous blood.

The following cases show the important role play of scientific evidence in the field of a criminal investigation. Custodial crime is a violation of fundamental rights subjecting an accused to undergo a scientific .test is a much better option than to let him face third-degree torture. Scientific techniques help in a speedy and fair trial. The concept of the fair trial and fair investigation is not only to be considered from the point of view of liberty or right of the accused only, the victim and the society also suffers where investigation becomes a casualty

Thus, Scientific evidence in criminal proceedings has played a key role in deciphering cases and has also resulted in a quick and steady justice system.

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