Narco-Analysis Test and it’s Constitutional Validity

‘Investigation’ is a search for something especially done to discover facts which are usually hidden and are not easily known. The investigation of crime encompasses “the collection of information and evidence for identifying, apprehending, and convicting suspected offenders.” or in the words of professor Ralph Turner, a pioneer in the field, “the reconstruction of a past event.”[1] The concept of criminal investigation can be traced back to thousands of years, to early times in China and Asia, as well as the middle east, where agents of the government used many legal and illegal approaches (most notably torture) to extract the truth. In the process of investigation whether it is criminal or any other investigation ‘interrogation’ plays a very crucial role which is done to extract information from the accused, suspects or others involved in the crime. It is an aid to further investigation. In seeking information from the people concerned or the suspects in crime, an investigator should be aware of two difficulties that may not immediately be recognized or comprehended. One is presented by those who are willing to talk but cannot recall (whole or in part) what was observed, or those who do not remember anything beyond the information already provided. The second difficulty is presented by those who refuse to talk, or do talk but withhold what might be of use, or attempt to misdirect the investigator by providing unproductive leads. In earlier times, to extract the truth or information from the person involved beating, arresting or torturing other family members and quite later third-degree methods were used to extract such information. But due to technological advancements and new modern techniques coming into picture we see a little rise and transition from third degree methods to modern techniques which are used by the investigating agencies to extract information and facts.

Techniques used are of two kinds

  1. Traditional for eg Third-degree methods or,
  2. Modern like DDT also called as ‘Deception Detection Test’ for eg. Narco-analysis test or the truth serum, polygraph or lie-detector test, brain-mapping or P300.

Lie detection or polygraph tests are widely used in the investigation. It is a mechanical device designed to ascertain whether a subject (a person on whom such tests are conducted) is telling the truth. It records any changes in blood pressure and pulse, breathing rate, and the electrical conductance of the skin, known as GSR (galvanic skin response). The instrument is based on the idea that ordinarily a person is under stress when telling a lie; therefore, physiological responses to psychological stimuli (the questions) are produced that can be detected and measured. They can be interpreted to mean that the subject is telling the truth, that he or she is lying, or the result may be inconclusive. Whereas, on the other hand narco tests are conducted in rarest of rare cases on the subject as it involves injecting a drug into subject’s body which can be dangerous.  In this article, researcher intends to analyse various facets dealing with narco-analysis test like-

  1. Whether Narco-analysis tests has the constitutional validity?
  2. Whether such results hold any evidentiary value?
  3. Are they admissible in the court of law?
  4. Is prior consent of the subject a pre-requisite?

What is Narco-Analysis test?

The word Narco analysis was first coined by Horseley. It’s derived from the Greek word called ‘Narkc’ which means anaesthesia. It involves injecting a drug called sodium pentothal with distilled water into the body of subject (accused or any suspect) in which the subject’s imagination is neutralised and they are expected to divulge true information in relation to the crime. Hence, Narco-analysis test is also called as the truth serum. The subject on such administration enters ‘twilight stage’ the stage between conscious and unconscious state of mind the subject enters in that situation were his actions are beyond his control. Narco analysis test poses a lot of difficulties and is usually conducted with due caution and care considering various situations. Administering too little narcotics in to the body of the subject may lead to further faking scenarios and administration beyond the limit so provided may lead to further difficulties as the subject may face coma or other health issues. In India Narco tests are administered in the presence of experts in the field like anesthesiologist, psychiatrist, clinical psychologist, doctors, supporting nursing staff, videographer etc. Before administering such dose prior consent of the court and of the subject is taken, the person undergoing the test is explained the whole procedure in addition with the consequences of such administration before acquiring consent. The whole process is video recorded and the report is further submitted to the investigating authorities.

Constitutional validity of Narco-analysis test

Narco-analysis tests are conducted in rarest of rare cases. Narco-analysis tests do not hold any constitutional legal validity because the person undergoing such tests is in the semi-conscious or unconscious state of mind and is not in the position to understand the true nature of questions so posed by the authorities because of which the results do not hold any evidentiary value and hence are not admissible in the court of law. But it does act an aid for further investigation. Narco-analysis tests, lie-detector or polygraph, brain-mapping or P300 without prior consent of the accused or the subject would be violative of Article 20(3) of the Indian Constitution which deals with the privilege against self-incrimination. The article states that “no person accused of any offence shall be compelled to be a witness against himself”. Subjecting accused to such tests has been considered as a blatant violation of Art 20(3) of the Indian constitution. Various questions were raised by human rights activists and other professionals with regard to it’s constitutionality as the subject is deprived of his freedom of privacy which is an integral part of Right to life and personal liberty under Article 21 of the Indian constitution. It was observed in State Bombay v. kathikalu [2]that the to attract Article 20(3) it must be shown that the person was compelled to undergo such tests by way of any threat or duress etc.

Under the Indian constitution Article 20(3) is not restrictive in manner it has wide meaning in itself as the article covers the person’s right to remain silent. It is this right which assures personal privacy of an individual. Right to silence was first pronounced in Nandini satpathy vs PL Dani[3] were court said that no one can forcibly extract statements from the accused, who has the right to remain silent during the process of investigation especially interrogation, by administration of such tests like Narco would lead to forcible intrusion into one’s mind which is against the right to privacy of an individual. The court went a step ahead in M P Sharma v. Satish Chandra[4] and asserted that Article 20(3) of the Indian constitution uses the term ‘to be a witness’ and not ‘to appear as a witness’ which broadens the scope outside the court premises that no person accused of any offence shall be compelled to speak against himself. Section 161(2) of the criminal procedure code also deals with similar provision it states that “ every person is bound to answer truthfully all questions, put to him by the police officer, other than the questions the answers to which would have a tendency to expose that person to a criminal charge, penalty or forfeiture”. Hence any such statement extracted from the accused or any suspect in the crime, while he is under the state of dis-inhibition would be held constitutionally invalid and will not hold any evidentiary value in the court of law.  But in certain cases it is the discretion of the court to record the statement as an evidence or not, by first taking into considerations all circumstances.

Admissibility of Narco-analysis tests

Before dwelling into whether Narco tests are admissible in the court of law as an evidence, it is evident to understand what admission means. Admission under Indian Evidence act, 1872 is any statement oral, documentary, electronic or otherwise given by any party or his representative in any concerned matter relating to any subject matter of the suit in the court of law. In Ahmed Saheb v. Sayed Ismail[5] supreme court asserted that admission is a substantial piece of evidence which can be further used to prove or disprove the facts in a given case.

In India, the term Narco-analysis is not foreign and such tests were conducted in various cases like Godhra carnage case 2002, Arun bhat’s kidnapping case, Telgi’s case in 2003, Arushi Talwar Murder case and the very recent one is Uttar pradesh’s Hathras rape case. Questions with regard to admissibility were raised by many defence counsels and human rights activist as it is against Right to privacy of an individual which is an integral part of life and personal liberty under Article 21 of the Indian constitution. The administration of Narco tests do yield information which is a basis for further investigation, but critics are skeptical with regard to its pureness or truthfulness as the person is not in the state of conscious mind which is an important factor. The results of Narco-analysis tests can be used as a corroborating evidence (supporting evidence) which will further aid to investigate primary or material evidence. The narco tests do hold validity in some circumstances like to further help agencies to find the real culprit etc  but are not admissible in the court of law as an evidence. But if the result itself is not admitted due to some technicalities or complexities it won’t be used as a corroborative evidence either. The Supreme court in Selvi V. State of karnataka [6] further went on to state, administration of Narco-analysis or lie-detector tests without prior consent is unethical and would infringe the subject’s right to privacy.

The picture with regard to admissibility and constitutionality of such tests is now clear in India, as such tests holds some value in investigation or as a corroborative evidence. But any submission by the subject which is not voluntary or willful cannot be made admissible. Hence, to note here, is the consent which is voluntarily given with no compulsion and force from the authorities, before acquiring consent with regard to Narco-analysis tests full disclosure of facts and procedure to be adopted shall be explained. The subject before undergoing the tests is made full aware of all the facts which he deserves to know. Courts while considering any statement obtained by way of such administration will take into notice the consent whether obtained or not, and whether due legal process is undertaken prior the administration of such tests.

Approach of the judiciary towards Narco tests

The judiciary’s approach especially the apex courts have changed over the period of time, due advent and latest development in technology everyone is witnessing the smoothness in working of the system let it be in investigation or any other. Judiciary steps in whenever the individual’s basic rights are violated and in such cases if any case comes up which portrays blatant violation of human rights and other freedoms judiciary will actively play a role to struck down the practice. Hence, the courts may allow to record the statements arrived from such tests as an evidence only when it’s prima facie observed that there was willful submission made by the subject to undergo the tests like narco or in other cases polygraph or brain-mapping.The court in Rojo George v. Deputy Superintendent of Police[7] observed that modern or conventional techniques in the investigation are need of the hour but the administration of such tests shall be conducted in the presence of experts.

Criticisms of Narco-analysis test

Narco-analysis tests and other modern techniques like brain mapping or P300, Lie-detector tests or Polygraph which are used to extract the truth from the accused or suspects in the crime have gained the attention not just in India but all over the globe. Various technologies not just in criminal investigation but other areas also have made the task much easier. The investigators are now inclined more towards using such techniques like narco tests and polygraph as it has made their job easier. But criticisms are still faced by many like how reliable such tests could be? Faking scenarios, admissibility and evidentiary value of such extracted facts and statements. The courts have over the period of time has made the point clear with respect to its position in India.


Over the period of time various shifts and trends have been followed by the investigating departments to investigate the crime. Interrogation to extract confessions and facts plays quite an important role. We as a society need to adopt the changes I technology but the misuse should be avoided at any point of time. The use of new technologies should be a welcome step in criminal investigation. The record says in India there is high crime rate but low conviction rate and the problem is investigation. The change in investigation and interrogation is a big step in securing the aim of crime free society. The point to note here is also, no person should be compelled to put something on the table which may go against him in the future. Voluntary or wilful submission is prima facie imperative. No blanket application of such tests should be done but in rarest of rare cases or after taking into consideration all other factors. To conclude, conducting such tests is not a problem only if it is conducted all the guidelines and procedures which are essential.

[1] James W. Osterburgh /Richard H Ward- ‘Criminal Investigation- A method for reconstructing the past’

[2] AIR 1961 Cri LJ , Vol 2, 2007

[3] 1978 AIR 1025, 1978 SCR (3) 608

[4] 1954 AIR 300, 1954 SCR 1077

[5] AIR 2011 SC 2496

[6] Criminal Appeal No. 1267 of 2004

[7] 2006 (2) KLT 197

Author: Shweta Mehendale

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