This essay has been submitted by a law student. This is not an example of the work written by our professional essay writers.

Published: Fri, 02 Feb 2018

New Tools Of Criminal Investigation

Investigation is a very important part of any criminal proceeding and we have seen that all through the development of criminal administration system many newer methods of investigation have evolved. The search for effective aids to interrogation is probably as old as man’s need to obtain information from an uncooperative source and as persistent as his impatience to shortcut any tortuous path. 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 Narcoanalysis test. 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. This article purports to explain the details of Narcoanalysis test as a tool of interrogation in forensic science and also discusses constitutional imperatives and other legal aspects regarding the said test.

Recently police officials in some countries including India have turned to drugs for assistance in extracting confessions from accused persons, drugs, which are presumed to relax the individual’s defenses to the point that he unknowingly reveals truths, he has been trying to conceal. In India, where drugs have gained only marginal acceptance in police work, their use has provoked cries of “psychological third degree” and precipitated medico-legal controversies on one hand and has proved to be a scientific method pf interrogation on the other hand. This technique of using drugs for the purpose of investigation is called as “Narcoanalysis Test” also known as the “Truth Serum test”. According to Webster’s Dictionary, the word narcoanalysis had its origin in the 20th century and is coined from ‘narco-’ + ‘analysis’. It means psychoanalysis using drugs

to induce a state akin to sleep.

Narcoanalysis was rather unheard in India till recent past. However it has been in the news in the past few years as a new interrogation technique used by the various investigative agencies in India. It was first used in 2002 in the Godhra carnage probe. It was also in news after the famous Arun Bhatt kidnapping case in Gujarat wherein the accused had appealed to the NHRC and the Supreme Court against undergoing the narcoanalysis test. It was again in news in the Telgi stamp paper case and was made famous when Abdul Karim Telgi was subjected to the said test in December 2003 at a government hospital in Bangalore.

This project paper deals with imbalance created by these self –incrimination tests in the light of the fundamental rights given to us by our Constitution.

THE TESTS: A Basic understanding

With the crime graph climbing up a steep rate, the police interrogation techniques play a vital role in extracting the truth from the suspect. Some of the commonly used interrogation methods include the use of hypnosis, truth serum, voice analysis, fingerprint testing, handwriting evidence and DNA analysis. The scientific tools of interrogation namely- the Lie detector or the Polygraph test, the P300 or the Brain Mapping test and the Narcoanalysis or the Truth Serum test are the main three tests that have recently been developed for extracting confessions. These psychoanalytical tests are also used to interpret the behaviour of the criminal (or the suspect) and corroborate the investigating officers’ observations.


It is believed that if a person is administered a drug which suppresses his reasoning power without affecting memory and speech, he can be made to tell the truth. Some drugs have been found to create this ‘twilight state’ in some persons. These drugs are being administered in some countries including India. The term narcoanalysis was introduced in 1936 for the use of narcotics to induce a trance like state wherein the person is subjected to various queries. Under the influence of the drug, the subject talks freely and is purportedly deprived of his self-control and will power to manipulate his answers. The underlying theory is that a person is able to lie by using his imagination. In the narcoanalysis test, the subject’s imagination is neutralized and reasoning faculty affected by making him semi-conscious. The subject is not in a position to speak up on his own but can answer specific and simple questions. In this state it becomes difficult for him to lie and his answers would be restricted to facts he is already aware of. His answers are spontaneous as a semi-conscious person is unable to manipulate his answers.

Truth serums (or sera) are no serum at all. They are drugs sometimes used clinically. A few of the best known drugs are Seconal, Hyoscine (scopolamine), Sodium Pentothal, Sodium Amytal, Phenobarbital. Most commonly used drug for truth serum test is an anesthetic and sedative drug, Sodium Pentothal which when administered intravenously can make a person garrulous and confessional. Injected in continuous small dosages it has a hypnotizing effect on a person whop responds loquaciously when questioned. The narcoanalysis test is conducted by mixing 3 grams of Sodium Pentothal or Sodium Amytal dissolved in 3000 ml of distilled water. Depending on the person’s sex, age, health and physical condition, this mixture is administered intravenously along with 10% of dextrose over a period of 3 hours with the help of an anesthetist. Wrong dose can send the subject into coma or even result in death. The rate of administration is controlled to drive the accused slowly into a hypnotic trance. The effect of the biomolecules on the bio-activity of an individual is evident as the drug depresses the central nervous system, lowers blood pressure and slows the heart rate, putting the subject into a hypnotic trance resulting in a lack of inhibition.

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 instructing the doctors or hospital authorities to conduct the test. Personal consent of the subject is also required.


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.

Polygraph test is conducted in three phases- a pretest 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. 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.

The polygraph test was among the first scientific tests to be used by the interrogators.


This test was developed and patented in 1995 by neurologist Dr. Lawrence A. Farwell, Director and Chief Scientist “Brain Wave Science”, IOWA. In this method, called the “Brain-wave finger printing”; the accused is first interviewed and interrogated to find out whether he is concealing any information. Then sensors are attached to the subject’s 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 if the subject has connection with the stimulus i.e. picture or sound. The subject is not asked any questions.

Dr. Farwell has published that a MERMER (Memory and Encoding Related Multifaceted

Electro Encephalographic Response) is initiated in the accused when his brain recognizes noteworthy information pertaining to the crime. These stimuli are called the “target stimuli”. In a nutshell, Brain finger printing test matches information stored in the brain with information from the crime scene. Studies have shown that an innocent suspect’s brain would not have stored or recorded certain information, which an actual perpetrator’s brain would have stored.

The Forensic Science Laboratory in Bangalore is the first center in India which conducts the Brain-mapping or Brain-finger printing test. In USA, the FBI has been making use of “Brain mapping technique” to convict criminals.


Early in the 20th century, physicians began to employ scopolamine along with morphine and chloroform, to induce a state of “twilight sleep” during childbirth. Scopolamine was known to produce sedation and drowsiness, confusion and disorientation, incoordination and amnesia for events experienced during intoxication.

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 to interview under scopolamine two prisoners in the Dallas county jail whose guilt seemed clearly confirmed. Under the drug, both men denied the charges on which they were held; and both, upon trial, were found not guilty. Thus, Robert House concluded that a patient under the influence of scopolamine “cannot create a lie… and there is no power to think or reason”. His experiment and this conclusion attracted wide attention, and the idea of a

truth drug was thus launched on the public consciousness.

The phrase “Truth Serum” is believed to have appeared first, in the news report of Robert House’s experiment the Los Angeles Record, sometime in 1922. Robert House thereafter came to be known as the ‘Father of Truth Serum’.


The suggestion that drugs might facilitate communication with emotionally disturbed patients first camequite by accident in 1916, when Arthur S. Lovenhart and his associates at the University of Wisconsin were experimenting with respiratory stimulants. At about this time, police officials still attracted by the possibility that drugs might help in the interrogation of suspects and witnesses turned to a class of depressant drugs known as the Barbiturates. Barbiturates were first synthesized in 1903 and are among the oldest of modern drugs.

By 1935 Clarence W. Muehlberger, head of the Michigan Crime Detection Laboratory at East Lansing, was using barbiturates on reluctant suspects, though police work continued to be hampered by the courts’ rejection of drug induced confessions except in a few carefully circumscribed instances.

Three of the barbiturates which are used in narcoanalysis and have seen service as truth drugs are sodium amytal (anobarbital), pentothal sodium (thiopental), and to a lesser extent seconal (seconbarbital). During the Second World War, the technique of the so called truth serum was developed to help soldiers who had broken down under the strain of battle. Gradually a useful mental first-aid technique was developed which helped the unconscious to reveal its secret while the individual was under the influence of the narcotic. It was during this time that Sodium Pentothal was first used as a “truth drug”.


The uses of narcoanalysis drugs are two fold- they are used as “truth drugs” in police work and also used in the accepted psychiatric practice of narcoanalysis. The difference in the two procedures lies in their different objectives. The police investigation is concerned with empirical truth that may be used against the suspect, and therefore almost solely with probative truth. The usefulness of the suspect’s revelations depends ultimately on their acceptance in evidence by a court of law. The psychiatrist, on the other hand, using the same “truth drugs” in diagnosis and treatment of the mentally ill, is primarily concerned with psychological truth rather than empirical fact.


Simply put, narcoanalysis tests are unreliable. This has been well known for many decades. Studies and reviews from the 1940s and 1950s (and some dating back to the 1920s) in the US and UK demonstrated two major shortcomings of narcoanalysis. First, questioning suspects after injecting them with truth serum is ineffective on individuals who are determined to lie to investigators. According to one reviewer, “criminal suspects, while under the influence of barbiturate drugs, may deliberately withhold information, [or] persist in giving untruthful answers….”.

Second, the most pernicious inadequacy of narcoanalysis may be the risk of false confessions from innocent persons. Because the subject is in a highly suggestible state when under the influence of truth serum drugs, he or she is prone to give false or misleading answers to questions, especially if they are improperly framed [1] . Even some commentators favorably disposed to narcoanalysis admit the possibility that an improperly framed question may extract a confession from an innocent person, and that “unless supporting evidence is obtainable, the reliability of results of “truth serum” tests are open to serious question”. “The likelihood of a gross miscarriage of justice through undue dependence upon unreliable statements [made while under narcoanalysis] is entirely too great”. Unfortunately, some courts in India have not given due regard to the well-recognised limitations of narcoanalysis and have instead held that because such tests are “scientific”, and so long as they are conducted in the presence of an “expert”, they are permissible. [2] In their zeal to appear at the forefront of forensic science [3] (never mind that narcoanalysis has a pedigree almost a century old), these courts have failed to appreciate the dangers these tests represent.


The main provision regarding crime investigation and trial in the Indian Constitution is Art. 20(3). It deals with the privilege against self- incrimination. It has its equivalents in the Magna Carta, the Talmud, and the law of almost every civilized country.

USA: The Fifth Amendment of the US Constitution provides inter alia: “No person…shall be compelled in any criminal case, to be a witness against himself”.

BRITAIN: It is a fundamental principle of the common law that a person accused of an offence shall not be compelled to discover documents or objects, which incriminate him. The privilege is based on the policy of encouraging persons to come forward with evidence in courts of justice, by protecting them, as far as possible, from injury, or needless annoyance, in consequence of so doing.

INDIA: The privilege against `self incrimination is a fundamental canon of Common law criminal jurisprudence. The characteristic features of this principle are-

The accused is presumed to be innocent,

That it is for the prosecution to establish his guilt, and

That the accused need not make any statement against his will.

These propositions emanate from an apprehension that if compulsory examination of an accused were to be permitted then force and torture may be used against him to entrap him into fatal contradictions. The privilege against self-incrimination thus enables the maintenance of human privacy and observance of civilized standards in the enforcement of criminal justice. Art. 20(3) which embodies this privilege reads, “No person accused of any offence shall be compelled to be a witness against himself”.

On analysis, this provision will be found to contain the following components:

It is a right available to a person “accused of an offence”;

It is a protection against such “compulsion” “to be a witness”;

It is a protection against such “compulsion” resulting in his giving evidence against himself.

All the three ingredients must necessarily coexist before the protection of Art.20(3) can be claimed. If any of these ingredients is missing, Art. 20(3) cannot be invoked. The application of Narcoanalysis 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 Art. 20(3) of Constitution. It also goes against the maxim Nemo Tenetur se Ipsum Accusare that is, ‘No man, not even the accused 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 (be it under a hypnotic state of mind) it should stand to be rejected by the court. The main issue thus is the question of its admissibility as a scientific technique in investigations and its ultimate admissibility in court as forensic evidence.

In USA, in the case of Townsend v. Sain [4] , it was held that the petitioner’s confession was constitutionally inadmissible if it was adduced by the police questioning, during a period when the petitioner’s will was overborne by a drug having the property of a truth serum. In another famous case of US v. Solomon [5] , which directly debated the issue of narcoanalysis, the expert opinion given to the court established that “truth serum is now generally accepted investigative technique”. The experts said: “Adequate safeguarding against unreliability is possible”. However “narcoanalysis does not reliably induce truthful statements”.

But the other view regarding the legal validity of narcoanalysis test is that it is used as an aid for collecting evidence and helps in investigation and thus does not amount to testimonial compulsion. Thus it does not violate the constitutional provision regarding protection against self-incrimination.

Right against Self-incrimination

Article 20(3) of the Indian Constitution states that “no person accused of an offence shall be compelled to be a witness against himself”. This provision operates as a shield against the compulsion of testimony. Section 161(2) of the Code of Criminal Procedure, 1973 (CrPC) provides similar protection to the accused: a person is “bound to answer truly all questions” while being examined by the police except for those questions that “would have a tendency to expose him to a criminal charge or to a penalty or forfeiture”. The protection against self-incrimination is available to those who have already been charged

with the commission of an offence as well as suspects who have not been charged with anything. [6] “To be a witness” has been interpreted by the Supreme Court to mean “imparting knowledge in respect of relevant facts by an oral statement or a statement in writing, made or given in Court or otherwise” [7] . Further, “giving thumb impressions or impressions of foot or palm or fingers or specimen writings or showing parts of the body by way of identification” does not amount to self-incrimination because such acts do not constitute testimony and furnishing such samples does not amount to being a witness. [8] The court reasoned that because such identification evidence, unlike oral or written testimony, does not “have the tendency of incriminating the accused” and is relatively immutable, the ordinary protections against self-incrimination do not apply. [9] Informed consent is intrinsically linked to the exercise of the right against self incrimination. In Ramchandra Ram Reddy vs Maharashtra [10] , the Bombay High Court examined the issue of “whether requiring the accused to undergo these tests against his will would amount to compelling him to be a witness against himself”. The court concluded that “…such statement will attract the bar of Article 20(3) only if it is inculpating or incriminating to the person making it. Whether it is so or not can be ascertained only after the test is administered and not before.”

Further, the court was of the view that there are sufficient safeguards under the CrPC, Indian Evidence Act and the Constitution to prevent the admission of an incriminating statement in a court of law after such a statement is made under narcoanalysis. In Smt Selvi vs Karnataka, the Karnataka High Court took an extremely narrow view of “compulsion” and held that the only pain caused is from the injection prick and therefore, there is no compulsion [11] . The Karnataka High Court in Selvi, like the Bombay High Court in Ramchandra, also opined that it was impossible to know beforehand whether the statements made under narcoanalysis would be exculpatory or inculpatory, and therefore it would be “premature” to make a ruling with respect to the constitutionality of narcoanalysis under Article 20(3). [12] In effect, by classifying the concerns relating to consent as “premature”, the high courts failed to appreciate the problematic aspects of an involuntary statement made under a state of drugged semi consciousness.

Most troublingly, the lack of consent of the subject of narcoanalysis appears to be a non-issue for the high courts, which seem to take comfort in images of scientific or medical probity and clinical competence. But even in cases of medical procedures and scientific experiments on human subjects, consent of the subject is imperative. The image that should resonate in the minds of members of the court is that of the unwilling subject forcibly strapped down to a gurney, fighting and shouting all the way, until the syringe is plunged into his arm, the barbiturate is injected into the blood stream, and the drug-induced torpor overcomes his obvious resistance. Such administration of drugs against a subject’s will amounts to “compulsion”, defined in the English law dictionary as “a physical objective act and not the state of mind of the person making the statement, except where the mind has been so conditioned by some extraneous process as to render the making of the statement involuntary and, therefore, extorted” [13] (emphasis added).

Further, though some of the courts’ decisions appear to leave open the possibility that the

accused may challenge the admissibility of statements made under narcoanalysis at a later date (i e, during trial), that is cold comfort. The approach of the high courts fails to recognise the risk of innocent people falsely inculpating themselves under narcoanalysis. It also fails to comport with Indian constitutional and statutory protections that extend the

prohibition against compelled testimony backward in time far before the beginning of trial: “the protection afforded to an accused insofar as it is related to the phrase “to be a witness” is not merely in respect of testimonial compulsion in the court room but may well extend to compelled testimony previously obtained from him.” [14] What is more, the logic that we do not know whether a statement will be inculpatory or exculpatory before we ask questions under narcoanalysis is seriously flawed. That same logic would never be applied to questioning of a subject without the influence of drugs. Under such circumstances, the police could ask all manner of questions about a crime, and the subject

of the questioning could refuse to answer on the basis of possible self-incrimination.

Administration of the truth serum drugs chemically alters this sort of exchange, with the subject of questioning no longer able to make a considered judgment about whether what he is about to say is likely to incriminate him. The truth is no one knows what will come out of a suspect’s mouth if questioned under the influence of barbiturates; it could be inculpatory, exculpatory, or sheer nonsense. That should have been enough to give the courts pause. Lastly, the evidence gathered based on the results of a narcoanalysis test can be admitted as corroboratory evidence even if the actual words the accused uttered under narcoanalysis are not admissible. As lawyer Sriram Lakshman observes, “this is, arguably, a roundabout way of subverting the right to silence – acquiring the information on where to find the weapon from the subject when, in his right senses, he would not turn witness against himself”. Finally, while the results of the narcoanalysis tests conducted may not be admitted in court, the media broadcast of the results of the test conducted on Abdul Telgi, for example, has created a prejudice and vitiated the guarantee of a fair trial. In sum, the courts’ rulings have obliterated vital constitutional protections by so burdening the right to remain silent as to render it a dead letter.

Right to Life and Personal Liberty

Subjecting persons to injections of mind altering chemicals against their will is a violation of their right to privacy and may even violate their right to health. In this regard, it must be remembered that the drugs used in narcoanalysis are not simple over-the-counter medicines, but powerful drugs. Indeed, one of the most commonly used truth serum substances –sodium pentathol [15] – is the same substance that in larger dosages is used toinduce a deep coma-like state for executions by lethal injection in the US [16] . Indeed, a large dose of this drug is lethal. [17] Thus, we should not be overly quick in dismissing the health risks of narcoanalysis, especially if the drugs are not properly administered by a trained professional [18] . Though the Kerala High Court minimized the health risks of being injected with barbiturates by comparing narcoanalysis to medical procedures, [19] that comparison is inapt. The risks undertaken by a medical patient undergoing tests or even surgery are voluntary and intended by the doctor to ultimately heal the patient or at least relieve him of suffering. Obviously, the same cannot be said of the injection of drugs into a healthy individual for non health related purposes. But even if administered correctly, narcoanalysis raises profound privacy concerns.

Although right to privacy is not expressly mentioned in the Constitution, the SC has recognised that it falls within the ambit of the “personal liberty” [20] guaranteed under Article 21 of the Constitution. [21] Narcoanalysis raises Article 21 concerns by virtue of its invasion of the body and mind, which constitutes an invasion of privacy. The test directly intrudes on the mental processes of the subject, who lacks control over the questioning and his answers. There is a risk that the unconscious mind may reveal personal information, which is irrelevant to the investigation though highly embarrassing or even damaging to the subject, his family or his livelihood. It is therefore imperative to establish standards of confidentiality and other safeguards, as an individual’s privacy may be violated by the state only by a “procedure established by law”. [22] No such safeguards exist in India and therefore narcoanalysis amounts to a violation of the right to privacy if performed without consent.

It is no answer to say that an evidentiary rule of exclusion would keep statements the person makes while in a drugged stupor inadmissible in court. This does nothing to prevent the initial violation of privacy, which occurs when the subject of narcoanalysis first blurts out the information. Nor does it do much to protect the rights of the innocent and wrongly accused who may never be tried for anything at all. What is the remedy for their violation of privacy?

Regrettably, in Rojo George vs Deputy Superintendent of Police, the Kerala High Court held that narcoanalysis test “[does] not amount to deprivation of personal liberty or intrusion into one’s own privacy”. [23] Notably, the court did not fully substantiate its position and declined to address the intrusion into mental privacy. The court reasoned that because section 39 of the CrPC imposed a duty to furnish information to the police regarding crimes, there is no right to privacy to withhold such information. But this misunderstands the nature of the privacy concerns at issue here. The court imagined narcoanalysis as a fine scalpel to extract specific infor

To export a reference to this article please select a referencing style below:

Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.
Reference Copied to Clipboard.

Request Removal

If you are the original writer of this essay and no longer wish to have the essay published on the Law Teacher website then please click on the link below to request removal:

More from Law Teacher

We Write Bespoke Law Essays!