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Legal Admissibility of Narco Analysis And Polygraph Test In India

Narco - Analysis

The term Narco-Analysis is derived from the Greek word marks (meaning Anaesthesia or Torpor ) and is used to describe a diagnostic and psychotherapeutic technique that uses psychotropic drugs, particularly barbiturates, to induce a stupor in which mental elements with strong associated affects come to the surface, where they can be exploited by the therapist. The term narco-analysis was coined by Horseley.[1]

In the annals of police investigation, physical coercion has at times been substituted for painstaking and time consuming inquiry in the belief that direct methods produce quick results. Development of new tools of investigation has led to the emergence of scientific tools of interrogation like the narco analysis test.[2]

Narco Test refers to the practice of administering barbiturates or certain other chemical substances, most often Pentothal Sodium, to lower a subject's inhibitions, in the hope that the subject will more freely share information and feelings. A person is able to lie by using his imagination. In the Narco Analysis Test, the subject's inhibitions are lowered by interfering with his nervous system at the molecular level. [3]

In this state, it becomes difficult though not impossible for him to lie. In such sleep-like state efforts are made to obtain probative truth about the crime. Experts inject a subject with hypnotics like Sodium Pentothal or Sodium Amytal under the controlled circumstances of the laboratory. The dose is dependent on the person's sex, age, health and physical condition.[4]

The subject which is put in a state of Hypnotism is not in a position to speak up on his own but can answer specific but simple questions after giving some suggestions. The answers are believed to be spontaneous as a semi-conscious person is unable to manipulate the answers.[5]

The subject is then interrogated by the investigating agencies in the presence of the doctors. The revelations made during this stage are recorded both in video and audio cassettes. The report prepared by the experts is what is used in the process of collecting evidence. This procedure is conducted in government hospitals after a court order is passed. Personal consent of the subject is also required.[6]

Such tests are a result of advances in science but they often raise doubts regarding basic human rights and also about their reliability. Legal questions are raised about their validity with some upholding its validity in the light of legal principles and others rejecting it as a blatant violation of constitutional provisions.[7]

The application of narco analysis test involves the fundamental question pertaining to judicial matters and also to Human Rights. The legal position of applying this technique as an investigative aid raises genuine issues like encroachment of an individual's rights, liberties and freedom. Subjecting the accused to undergo the test, as has been done by the investigative agencies in India, is considered by many as a blatant violation of Article 20(3) of Constitution.[8]

It also goes against the maxim Nemo Tenetur se Ipsum Accusare that is, 'No man, not even the accused, he himself can be compelled to answer any question, which may tend to prove him guilty of a crime, he has been accused of'. If the confession from the accused is derived from any physical or moral compulsion, it should stand to be rejected by the court.[9]

Polygraph Or Lie Detection Test

It is an examination, which is based on an assumption that there is an interaction between the mind and body and is conducted by various components or the sensors of a polygraph machine, which are attached to the body of the person who is interrogated by the expert. The machine records the blood pressure, pulse rate and respiration and muscle movements. [10]

Polygraph test is conducted in three phases- a pre-test interview, chart recording and diagnosis. The examiner (a clinical or criminal psychologist) prepares a set of test questions depending upon the relevant information about the case provided by the investigating officer, such as the criminal charges against the person and statements made by the suspect.[11]

The subject is questioned and the reactions are measured. A baseline is established by asking questions whose answers the investigators know. Lying by a suspect is accompanied by specific, perceptible physiological and behavioural changes and the sensors and a wave pattern in the graph expose this. Deviation from the baseline is taken as a sign of lie. All these reactions are corroborated with other evidence gathered.[12]

It was Keeler who further refined the polygraph machine by adding a Psycho-galvanometer to record the electrical resistance of the skin.

Case Analysis

  1. Rojo George v/s Deputy Superintendent of Police [13]
    Facts: The suspect raised the plea that the proposed Narco-Analysis test is extremely problematical test which conducted after administering sodium pentathlon due to which the central nervous system effect, heart rate slows and blood pressure low. In the case, one Krishna Pillai confessed that he committed the offence. But the officers are not prepared to investigate whether that confession is true or not. The petitioner whole heartedly co-operated with the Investigating Agency while conducting Brain Mapping and Polygraph Test but the Investigating Agency was not able to collect any material. It is further averred that it is very difficult to determine the correct dosage of the drug to be administered on a subject since the same varies according to the age, sex, physical constitution and also mental attitude and will power. [14]

    Issue: It is argued that recording of a statement of a person undergoing Narco-Analysis will amount to testimonial compulsion and the same is violative of Article 20(3) of the Constitution. The immunity under Article 20(3) does not extend to compulsory exhibition of the body or giving blood specimen.[15]

    Ratio: The court’s considered view is that the same principle should apply to Narco-Analysis also because it is also a scientific test conducted by a team of scientists and not will amount to custodial interrogation by Police. Hence, while allowing the narco analysis test Court is of the opinion that in present day the criminals started to use very sophisticated and modern techniques for committing the crime. So the conventional method of investigation and questioning to the criminals will not be successful for solution and there is need to utilize some new techniques such as polygraph, brain mapping and narco analysis.[16]

    Held: It was held by the court in this case that Narco-Analysis is a scientific test conducted by the experts in the subject after taking all possible precautions. But such adverse reaction can happen while administering any medicine prescribed by doctors practicing modern medicine. So merely because there is a remote possibility of adverse reaction, use of such techniques in conducting investigation cannot be prevented.[17]
  2. KM. Seema Azad v/s State of U.P. 2013 [18]
    Facts: Also called Shashi murder case, in the case, Vijaysen Yadav, the main accused in the disappearance and murder case of Faizabad law student Shashi, has gone through polygraph and narco-analysis test. In this case, the incumbent BSP MLA, Anand Sen was convicted for a murder of a law student, Shashi of Faridabad.

    Role of the Test: Faizabad Chief Judicial Magistrate Shailesh Tiwari permitted the police on Friday to conduct the tests at the Central Forensic Laboratory in Bangalore. During his Polygraph and Narco Analysis Test, Vijay Sen (co – accused) said that the then minister had illicit relations with Shashi who eventually got pregnant. This left Anand Sen concerned according to Anand Sen who in his analysis reported the fact as was when known to Anand was asked Vijay to murder her. Vijay Sen in his trance like stage even revealed that after the said incident, Anand called him and told him that he had pushed her into a canal and strangulated her with his own hands and then disposed her body in the canal only. This was further corroborated with the help of phone calls between Anand and Vijay Sen from the site where Shashi was murdered.[19]

    Held: On the basis of Vijay’s statements recorded in the narco analysis and polygraph test, police arrested Anand Sen who was at the moment, minister in Mayawati cabinet. He continues to be in jail and bail application is pending before the Allahabad High Court.[20]
  3. Selvi Murugeshan v/s State of Maharashtra [21]
    Facts: In the mentioned case, Kavita Murugeshan, wife of Shiv Kumar and daughter of Selvi Murugeshan, a T.N sitting MLA lodged an FIR that her parents and their friend Govindraj, have murdered of her husband She had charged her parents for the murder of her husband as she has made love marriage with him, who belonged to the other caste, against the wishes of her parents. The victim was kidnapped while he was walking with his wife and next day he was found murdered at a field in Bangalore rural district. His head was smashed with a boulder and he was identified by his driving licence.

    Issue: In this sensational case, the investigating agency made demand from the court for conducting Narco-Analysis test. In this case, the question before the court was that whether conducting of Narco-Analysis test on the accused person will be a violation of Article 20(3) of Indian Constitution?[22]

    Ratio: The Court said that it will be depend upon the nature of the question which is to be asked from the accused person. Whether the statement made or any information given by the accused person will be either exculpatory or inculpatory and it is only inculpatory statement which is hit by the Article 20(3) of the Constitution. Therefore, it is premature to say regarding the nature of the statement or the information which the accused gives under Narco-Analysis test. Collection of evidence is permitted under the law by the police officer. Conducting the Narco Analysis test on the accused person is also part of collecting the evidence.[23]

    Role of the Test: The Narco-Analysis test showed the involvement of Selvi Murugeshan and her husband.

    Held: SC laid down the principle about conducting of Narco-Analysis that Narco-Analysis test cannot be conducted on the accused person without taking the consent from the accused person. It was further held by the Court that this test should be conducted in the presence of an expert.
  4. Nupur Talwar v/s Cbi & Anr 2012 [24]
    Facts: Famously known as Aarushi Talwar-Hemraj Double Murder Case, in which case Arushi, a 14 year girl was found to be dead in the home on 16-05-2008. The report was made by the parents of Arushi in the police station. The body of Aarushi Talwar was found in her bedroom. In the first information report Dr. Rajesh Talwar, her father pointed the needle of suspicion at Hemraj, a domestic help in the household of the Talwars. On 17.5.2008, the dead body of Hemraj was recovered from the terrace of the same house, i.e., house where Aarushi’s murder had also allegedly been committed. But after two days the dead body of Hemraj was also found on the terrace of the house of Arushi. [25]

First hand Investigations conducted by the police revealed the following points:

  • No blood of Hemraj was found on the bed sheet and pillow of Aarushi. There is no evidence to prove that Hemraj was killed in the room of Aarushi
  • Dragging mark on steps only indicate that murder has taken place somewhere other than the terrace.
  • On the clothes of Dr. Rajesh Talwar, only the blood of Aarushi was found but there was no trace of blood of Hemraj.
  • The clothes that Dr. Nupur Talwar was wearing in the photograph taken by Aarushi in the night of the incident were seized by CBI but no blood was found during forensic examination.
  • Murder weapons were not recovered immediately after the offence. One of the murder weapon i.e. sharp edged instrument could not be recovered till date and expert could not find any blood stain or DNA of victims from golf stick to directly link it to the crime.
  • There is no evidence to explain the finger prints on the scotch bottle (which were found along with blood stains of both the victims on the bottle).
  • The guards of the colony are mobile during night and at the entrance they do not make any entry. Therefore, their statements regarding movement of persons may not be foolproof.
  • A board of experts constituted during earlier investigation team has given an opinion that the possibility of the neck being cut by khukri cannot be ruled out, although doctors who have conducted postmortem have said that cut was done by surgically trained person with a small surgical instrument.
  • There is no evidence to explain the presence of Hemraj’s mobile in Punjab after murder.
  • The offence has occurred in an enclosed flat hence no eye witnesses are available

Role of the Tests: All the above findings raised suspicions as to whether the murders were committed by Dr. Rajesh and Nupur Talwar. The parents of Arushi were arrested by the police and were directed to take forensic tests. In this case, therefore they were subjected to Narco-Analysis test, Polygraph test and Brain mapping test. It was pleaded before the court that the report of these tests cannot be taken as evidence in the court of law. The CBI carried out narco-analysis test on Nupur and Rajesh Talwar between February 15 and 20, 2010 at the Forensic Science Laboratory in Gandhinagar, Gujarat. However, the investigations drew a blank.[26]

Held: No concrete evidence could be collected even after conducting the narco-test of the Talwar couple that could help in further investigations in the case. The test was conducted to find out if Nupur Talwar or Rajesh Talwar knew anything about the case, but they knew nothing different about the murder of the teenage girl.

There is urgent need for the application of forensic science in the criminal justice delivery system. The use of scientific or forensic evidence in criminal trials not only identifies the actual guilty but also prevents the innocent from being convicted wrongly. The principle of the Indian legal system is based on the fact that until proved guilty, a person is innocent and an innocent cannot be convicted even if a hundred criminals are surrendered.

With the above objective in mind, subjecting a person to narcoanalysis without his consent will be surely undermining his individual rights which are absolutely negating the principle of a right based society.

The use of scientific proof in a forensic setting has proven problematic for both judges and attorneys because most of them are not technically trained. Much of the difficulty encountered by courts when facing scientific evidence lies not in a lack of understanding the underlying science but in the task of choosing between competing scientific explanations.

Law is a living process, which changes according to the changes in society, science, and ethics and so on. The Legal System should imbibe developments and advances that take place in science as long as they do not violate fundamental legal principles and are for the good of the society. The Central government must make a clear policy stand on narco analysis because what is at stake is India’s commitment to individual freedoms and a clean criminal justice system.




  1. Fred E. Inbau, ‘The Admissibility Of Scientific Evidence In Criminal Case’
  2. Kriti Das, ‘Narco-Analysis: A Breakthrough In Indian Investigation’, The Viewspaper, 2009.
  3. Sonakshi Verma, ‘The Concept Of Narcoanalysis In View Of Constitutional Law And Human Rights’ Available At Http://Www.Rmlnlu.Ac.In/Webj/Sonakshi_Verma.Pdf
  4. Vikas Gupta, “Constitutional Validity Of Narco-Analysis Test In Forensic Science” 49, Journal Of The Indian Law Institute 531 (2008).
  5. Satyendra Kaul Zaidi And Mohd,. Hasan Zaidi, Narcoanlysis, Brain Mapping, Hypnosis And Lie Detector Tests, In Introduction Of Suspect 432 (Alia Law Agency, Allahabad, 2008).
  6. S.L. Vaijia, “Narco-Analysis –An Aid To Crime Investigation, 2013.
  7. Abhyudaya Agarwal & Prithwijit Gangopadhyay, ‘Use Of Modern Scientific Tests In Investigation And Evidence: Mere Desperation Or Justifiable In Public Interest’, (2009) 2 Nujs Law Review 31.
  8. Lakshman Sriram, “Narco-Analysis And Hard Fact”24, Frontline 97, (2007).
  9. J.M. Mac Donald, “Narco-Analysis And Criminal Law”, A.M.J.Psychiatry1954:111:283. 58 Kalvakota Srinivas Rao “Narco-Analysis” Altj 14 (2008).
  10. The Indian Journal Of Criminology And Criminalistic, Volxii, May-Aug.2003, 1.
  11. Rajesh Punia “Narco-Analysis-Investigating Tool Or A Torture?”
  12. A.K.Kala, Of Ethically Comprising Position And Blatant Lies About ‘Truth Serum’, Indian J. Psychiatry 6-9(2007).
  13. 2009crilj2189 (All)
  14. Satyendra K. Kaul And Mohd. H. Zaidi, Narcoanalysis, Brain Mapping, Hyponsis & Lie Detector Tests In Investigation Of Suspect, Alia Law Agency, Allahabad, 2008, Pp. 109-110.
  15. Schmalleger Frank, Criminal Justice Today, An Introductory Text For Twenty First Century, Fourth Edition, 1997.
  16. Barcelona Panda, ‘Narcoanalysis And Its Evidentiary Value In India’, (2011) Pl July
  17. Satyendra Kaul And Mohd. H. Zaidi, Narco-Analysis, Brain Mapping, Hypnosis & Lie Detector Test, An Interrogation Of Suspect 438(Alia Law Agency, Allahabad 2008).
  18. Criminal Appeal No.1055 Of 2011, Alternate Citation: 115crilj 22(2009).
  19. Naresh Kumar And Ved Pal Singh,”Narco-Analysis Test In Investigation Process: Law And Judiciary” Xiv, Mdu Law Journl108 (2009).
  20. Deepak Ratan And Mohd. Hasan, Zaidi, Forensic Science In India And The World 357 (Allahabad Law Agency, Allahabad, Edn. 2008).
  21. Air 1980 Sc 593
  22. M.Sivananda Reddy, “Narco-Analysis And Truth Serum” ,Criminal Investigation Departiclements Of Andhra Pradesh ,Available At Www.Cidap,Gov.In /Document/Narco-Analysis
  23. Rajesh Punia “Narco-Analysis Investigating Tool Or A Torture?”
  24. Criminal Appeal No. 68 Of 2012
  25. B. R. Sharma, ‘Forensic Science In Criminal Investigation’, Ed. 4 (New Delhi: Universal Law Publishing Co. Pvt. Ltd. 2003) P. 33-34
  26. A.K.Kala, Of Ethically Comprising Position And Blatant Lies About ‘Truth Serum’, Indian J. Psychiatry 6-9(2007).
  27. St. No. 439 Of 2007

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