Dna Profiling In Forensic Science And Criminal Investigations Law Essay

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Criminal investigation is a subject that figures extensively in governmental policies, media and public imagination. In addition to fictional accounts in books, movies and television, it has been in the focus of many official reports and enquiries (for instance the Malimath Committee Report). Criminal investigation is a staple of literary fiction and other media. From Sherlock Holmes through to modern day best sellers like Ian Rankin, Patricia Cornwel and P.D. James, criminal investigation fills bookshelves across the world. [1] 

In any criminal investigation, interrogation of the suspect and accused plays a pivotal role in extracting the truth from them. Since time immemorial several methods, most of which were based on some form of torture, have been used by the investigating agencies to extract information from accused and suspects. With the advancement of science and technology, sophisticated methods like 'lie detection test' have been developed which do away with the use of 'third degree torture' by the police. The scientific tools of interrogation namely - the Lie Detector or the Polygraph test, the P300 or the Brain Mapping test, and the Narco Analysis 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 behavior of criminal/ suspect and corroborate the investigating officer's observations. [2] 

Science and technology has proved to be an asset to criminal investigation. The Brain Mapping, Narco Analysis, DNA Fingerprinting, and Polygraph test have emerged as the most powerful techniques in helping the law enforcement agencies in administration of the criminal justice system. While investigating the case some criminals prove to be a hard nut to crack. In such cases, to procure evidence, the investigating teams generally tend to use illegal means such as third degree torture methods. However, the abovementioned recent advanced scientific tools have proved to be an efficient substitute by which the investigating officer digs out the concealed information or evidence from the suspects. However, there has been a lot of debate on the validity of these techniques because these are alleged to violate the right of the accused against self-incrimination under Article 20(3) of the Constitution of India. Further, it is also contended that these tests violate the right to privacy under Article 21 of the Constitution of India.

As science has outpaced the development of law or at least the laypersons understanding of it, there is unavoidable complexity regarding what can be admitted as evidence in court. In a spate of high-profile cases, such as those of the Nithari murders, Abu Salem and the Mumbai train blasts, suspects have been whisked away to undergo an interview, drugged with the barbiturate sodium pentothal. [3] 

The Malimath Committee (2003) devoted an entire chapter on the modern techniques of investigation and it is the contention of the authors that these can help improve capabilities of the police in apprehension of criminals, curtail unnecessary arrests, reduce response time, avoid use of third degree methods in detection and interrogation, improve prospects of proof through scientific evidence, etc. Some of these high-tech tools are DNA fingerprinting, cyber forensics, narco analysis, and brain-mapping. [4] 




Deoxyribonucleic Acid Profiling (also called DNA testing, DNA typing, or genetic fingerprinting) is a technique employed by forensic scientists to assist in the identification of individuals on the basis of their respective DNA profiles. DNA profiles are encrypted sets of numbers that reflect a person's DNA makeup, which can also be used as the person's identifier. DNA profiling is not be confused with full genome sequencing. It is used in, for example, parental testing and rape investigation. DNA fingerprinting, the term coined by Prof. Alec Jeffreys is often referred to as DNA profiling as the former has a tendency to restrict the scope of its application by creating a relation to dermatoglypic fingerprints. This is considered by certain authorities to be a misnomer in relation to DNA. [5] 

DNA fingerprinting or DNA profiling is becoming a new method of identification that analyses and compares the fragments of deoxyribonucleic acid from separate independent sources. If used with care and precision, it can be a useful and powerful method of identification. DNA evidence has been used in thousands of important cases in India. For example, the Parmananda Swami case, the Rajiv Gandhi assassination case [6] and the CRPF false gang rape case (Bhongir, Andhra Pradesh).

DNA tests are highly effective because every person's DNA is unique except for identical twins. The greatest asset of DNA is that it cannot be tampered with. DNA tests can be used to establish parentage of a child, detect crimes, and identify mutilated dead corpses. They are of immense help in criminal justice administration and in some civil disputes like succession, inheritance, etc.


The DNA profiling technique was first reported in 1984 by Sir Alec Jeffreys at the University of Leicester in England, and is now the basis of several national DNA databases. Dr. Alec Jeffreys' genetic fingerprinting was made commercially available in 1987, when a chemical company, ICI, started a blood-testing center in England. DNA was discovered in 1869 by Swiss scientist Frederick Micscher. It was first used in England by the police in the infamous Enderby case involving two girls who had been raped and murdered.


DNA analysis is widely applied to determine genetic family relationships such as paternity/maternity, siblingship and other kinships. During conception, father's sperm cell and mother's egg cell (each containing half the amount of DNA found in other body cells) meet and fuse to form a fertilized egg, which is called a zygote. The zygote contains a complete set of DNA molecules, a unique combination of DNA from both parents. This zygote divides and multiplies into an embryo and later, a full human being.

DNA does not change once it is formed at conception. At each stage of development all the cells forming the body contain the same DNA, half from the father and half from the mother. This fact allows the relationship testing to use all types of samples including loose cells from the cheeks collected using buccal swabs, blood or other types of samples. The process begins with a sample of an individual's DNA (typically called a "reference sample"). The most desirable method of collecting a reference sample is the use of a buccal swab, as this reduces the possibility of contamination. When this is not available (e.g. because a court order may be needed and not obtainable), other methods may be used to collect a sample of blood, saliva, semen, or other appropriate fluid or tissue from personal items (e.g. toothbrush, razor, etc.) or from stored samples. Samples obtained from blood relatives (biological relatives) can provide an indication of an individual's profile, as could human remains which had been previously profiled. [7] Courts in India have time and again held that the evidence for proving non-access must be strong, distinct, satisfactory and conclusive. DNA tests can be strong evidence as they are correct up to 99%, if positive, and 100%, if negative.


In Vasu vs. Santha [8] and Gautam Kundu vs. State Of West Bengal [9] , the court has laid down certain guidelines regarding DNA tests and their admissibility to prove parentage. These are:

That the courts in India cannot order blood test as a matter of routine.

Wherever applications are made for such prayers in order to have roving inquiry, the prayer for blood test cannot be entertained.

There must be a strong prima facie case in which the husband must establish non-access in order to dispel the presumption arising under Section 112 of the Evidence Act.

The court must carefully examine as to what would be the consequence of ordering the blood test; whether it will have the effect of branding a child as a bastard and the mother as an unchaste woman.

No one can be compelled to give sample of blood for analysis.


Though there is no specific DNA legislation enacted in India, Section 53 and 54 of the Code of Criminal Procedure, 1973 provide for DNA tests impliedly and they are extensively used in determining complex criminal problems.

Further, the court in several instances laid down that blood-grouping test is useful to determine the question of disputed paternity. It can be relied upon by courts as a circumstantial evidence, which ultimately excludes a certain individual as a father of the child. However, it is to be noted that no person can be compelled to give sample of blood for analysis against his/her will and no adverse inference can be drawn against him/her for this refusal.

Section 53 deals with examination of the accused by a registered medical practitioner at the request of police officer if there are reasonable grounds to believe that an examination of the person will afford evidence as to the commission of the offence.

Section 54 provides for the examination of the arrested person by the registered medical practitioner at the request of the arrested person. The Law Commission of India in its 37th report stated that to facilitate effective investigation, provision has been made authorizing an examination of arrested person by a registered medical practitioner, if from the nature of the alleged offence or the circumstances under which it is alleged to have been committed, there are reasonable grounds for believing that an examination of the person will afford evidence.

Section 27(1) of the Prevention of Terrorism Act, 2002 says that when an investigating officer requests the court of the Chief Judicial Magistrate or the court of the Chief Metropolitan Magistrate, as the case may be, in writing for obtaining sample of handwriting, fingerprints, foot prints, photographs, blood, saliva, semen, hair, voice of any accused person or a reasonable suspect to be involved in the commission of an offence under this Act, it shall be lawful for such court to direct that such samples shall be given by the accused person to the police officer either through a registered medical practitioner or otherwise, as the case may be.


The suggestions drawn by the Malimath Committee report, inter alia, include the following:

Section 313 of the Code of Criminal Procedure, 1973 must be amended so as to draw adverse inference against the accused if he fails to answer any relevant material against him thereby making it easy for the law enforcers to use DNA tests against him.

A specific law should be enacted giving guidelines to the police for setting uniform standards for obtaining genetic information and creating adequate safeguards to prevent misuse of the same.

A national DNA database should be created which will be immensely helpful in the fight against terrorism and hardened criminals.

More well-equipped laboratories and suitable infrastructure should be established to handle DNA samples and evidence so that timely reports are available.

Efforts should be taken to create more awareness among general public, prosecutors, judges and police machinery. [10] 





Scientific tests generally don't have legal validity as confessions made by a semi-conscious person are not admissible in the court of law. The court may, however, grant limited admissibility after considering the circumstances under which the test was obtained. In the main, these tests can only assist police investigations. A few democratic countries, most notably India, still continue to use these test in various cases. But the other view regarding the legal validity of these tests 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 is still a question whether these methods violate the constitutional provisions regarding protection against right to self-incrimination and right to privacy.


The main provision regarding investigation and trial under the Constitution of India is contained under Article 20(3). It deals with the privilege against self-incrimination. The privilege against self incrimination is a fundamental canon of common law criminal jurisprudence. On careful analysis, it can be found that Article 20(3) contains the following components:

It is a right available to a person accused of an offence.

It is a protection against compulsion to be a witness against oneself.

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

All the three ingredients must necessarily co-exist before the protection of Article 20(3) can be claimed. If any of these ingredients is missing, Article 20(3) cannot be invoked. The legal position of applying these techniques as an investigative aid raises genuine issues like encroachment of an individual's rights, liberties and freedom. [11] 

In Ramchandra Ram Reddy vs. State of Maharashtra [12] , the court was posed with the question whether P-300, Lie Detector and Narco Analysis tests are violative of Article 20(3). The question which fell for consideration therefore, was whether such statement can forcibly be taken from the accused by requiring him to undergo the Truth Serum Test against his will. Such statement will attract the bar under Article 20(3) only if it is incriminating the person making it. Whether it is so or not can be ascertained only after the test is administered. Therefore, there is no reason to prevent administration of this test since there are enough protections available under the Indian Evidence Act, 1872, the Code of Criminal Procedure, 1973, and under the Constitution of India, to prevent inclusion of any incriminating statement if any of it comes out after administration of the test. Insofar as the Narco Analysis is concerned, enough protection exists, recourse to which can be taken if and when the investigating agency seeks to introduce such statement as evidence. The court dismissed the petitions filed against these tests and held that these tests do not compel the accused or witness to incriminate himself and there is therefore no question of violation of Article 20(3) of the Constitution.

The Supreme Court of India in Swati Lohda's case [13] has held that taking of blood samples from accused person's body is not violate of Article 20(3), but at the same time, accused can refuse to give blood samples. However, where the court makes direction for blood tests and the accused refuses then, the court may use the refusal or failure of the accused as corroborative evidence or adverse inference against him can be drawn. The court may infer that some impediment was there and that is the reason why he said no. The court said that the blood sample is in itself no testimony at all. It is only a material for comparison in order to lend assurance to the court that an inference based on other pieces of evidence is relevant.

However, in Narco Analysis test, the question of compulsion does not arise because the prior consent of the person who is supposed to undergo such a test is always taken. In fact, the Supreme Court in State of Bombay v. Kathi Kalu Oghad [14] held that there is no compulsion when a police officer in investigating a crime against a certain individual asks him to do a certain thing. The fact that a person was in police custody when he made the statement is not a foundation for an inference that he was compelled to make the statement. The mere questioning of an accused by a police officer resulting in a voluntary statement which may ultimately turn out to be incriminatory is not compulsion. Considering all these it can easily be concluded that Narco Analysis does not violate Article 20(3) to the extent that the person undergoing such a test is not compelled to do so; rather it is done with the consent of the person who has full knowledge of such a test. [15] 


3.3.1 Section 45: Opinions of experts

When the court has to form an opinion upon a point of foreign law or of science, or art, or as to identity of handwriting or finger-impressions, the opinion of persons skilled in such foreign law, science or art, or in questions as to identifying handwriting or finger-impressions, are relevant facts. Such persons are called experts. Section 45 of the Indian Evidence Act, 1872 does allow expert opinions in certain cases. However, this section is silent on other aspects of forensic evidence that can be made admissible in court in criminal proceedings. The right against forced self-incrimination, widely known as the Right to Silence, is enshrined in the Code of Criminal Procedure, 1973 and the Constitution of India.

3.3.2 Section 27

The information gathered from scientific tests can obviously be used for collecting further information or for getting some further leads or clues. This is empowered by Section 27 of the Indian Evidence Act, 1872. This sections says, "when any fact is deposed to as discovered in consequence of information received from a person accused of any offence, in the custody of a police officer, so much of such information, whether it amounts to a confession or not, as relates distinctly to the fact thereby discovered, may be proved." It clearly means that any incriminating evidence will not be used against the accused but so much information which leads to the discovery of an evidence is admissible in evidence. Similarly, the scientific evidence collected from a person may not be admissible but if corroboration comes from other evidence this may be held admissible.

3.3.3 Section 46: Facts bearing upon opinion of experts

Facts, not otherwise relevant, are relevant if they support or are inconsistent with the opinion of experts when such opinions are relevant.


The right to privacy demands that data extracted from DNA profile should be used to establish the identity of the persons and nothing more. DNA profile may include much more information like medical and genetic data which the individual may like to withhold under the right of privacy. The privacy concern will raise issues like:

What information should be stored?

How it should be stored?

Who will have access to this information?

Therefore, to protect such concern a DNA Database should include only information that reveals an individual's identity and nothing more. [16] 


In India, there are difficulties in the acceptance of scientific evidence in courts. Sections 161 and 162 of the Code of Criminal Procedure, 1973, Section 25 of the Indian Evidence Act, 1872, and Article 20(3) of the Constitution of India, pose difficulties.

Even though several convictions have taken place on the basis of DNA fingerprinting, it is still far away from accepting polygraph test in evidence even if it is conducted by a person who is not a police officer. So, it can be said that there are multiple hindrances in the admissibility of scientific evidence. [17] 


Article 14(3)(g) of the International Covenant on Civil and Political Rights, 1966 mandates that a person is not to be compelled to testify against himself or to confess his guilt.

The Universal Declaration of Human Rights, 1948 under Article 11.1 says, "Everyone charged with the penal offence has the right to be presumed innocent until proved guilty according to law in a public trail at which he has had all guarantees necessary for his defense."

The European Convention on Human Rights under Article 6(1) states that every person charged has a right to a fair trial, and Article 6(2) states that everyone charged with a criminal offence shall be presumed innocent until proved guilty according to law of the land.



We know that these scientific techniques are used to curtail unnecessary arrests, reduce response time, avoid use of torture in investigation, improve prospects of proof through scientific evidence, but at the same time these techniques are criticized on various points.

Now if we talk about one of methods of scientific investigation i.e. Narco Analysis, it is the administering of chemical drugs by the police to a suspect or witness in order to extract information from him/her by asking questions while in a drugged state. Three grams of sodium pentothal dissolved in three litres of distilled water are injected in one's veins along with ten per cent dextrose, slowly over three hours. This injected cocktail is believed to depress the body's central nervous system, putting the subject in a state of trance, hence suppressing the rational faculties that would be present if questioned when fully awake.

While the dubious practice on injecting drugs such as scopolamine, sodium amytal and sodium pentothal has been practiced and discarded by a number of countries over the last century, it has been prevalent in India for only half a decade. However, it is gaining popularity in police investigations and has been used in a number of high-profile cases, including Abu Salem case, Abdul Karim Telgi case, Hyderabad bomb blasts case and Nithari killings case. Narco Analysis has also increasingly been used against activists, including against Arun Ferreira, Ashok Reddy, Naresh Bansod and Dhanendra Bhurle, who were arrested on May 9, 2007 by Nagpur police under the Unlawful Activities (Prevention) Act. [18] 

There are certain issues of grave concern. Formal law and modern jurisprudence include certain liberal principles in theory, that a person is innocent until proven guilty, that a suspect or an under-trial cannot be physically or mentally pressured in any way to extract information, that a witness or a suspect has the right not to incriminate one-self, that a witness has a right to remain silent. Narco Analysis violates all these settled principles of law.

Narco Analysis test is a restoration of memory which the suspect had forgotten. This test result may be doubtful if the test is used for the purposes of confession. This test is not recommended as an aid to criminal investigation. In medical uses, like in treatment of psychiatric disorder, the test may be useful. Unless the test is conducted with the consent of the suspect it should not be used in criminal investigation. [19] 

The question of consent is the important argument against these techniques. In the well-known case against Gujarat Deputy Inspector General of Police, Vanzara, (accused in the case of fake encounter killing of Sohrabuddin), the Ahmedabad Metropolitan Magistrate underlined that such tests cannot be carried out without the express consent of the accused. In November 2006, the Supreme Court ordered a stay on Narco Analysis being carried out without consent on K. Venkateswara Rao, in a case involving the Krushi Cooperative Urban Bank. However, such welcome caution is likely to be thrown to the winds when the accused is dalit, poor, or is an activist whose politics is considered suspect by the state, as has happened in the case of Arun Ferreira. [20] 

There are dangerous side-effects. It is believed that sodium pentothal, if administered improperly, could lead to coma and even death. The possible life-threatening side effects of sodium pentothal include harmful effects on blood circulation and breathing, apnoea (stopping of airflow during sleep) and anaphylaxis (a rapidly progressing, life-threatening allergic reaction of the immune system). According to a research, its effects on the central nervous system "may lead to retrograde amnesia, emergence delirium, besides many other side effects". Consent implies informed consent. There is little doubt that the subjects are unaware of these dangers when their 'consent' is being secured.

Another technique of investigation which is the subject of criticism is the polygraph test. It is a lie-detection method in which it is assumed that when you are telling a lie, i.e. when your mind is trying to deceive it has a direct physiological impact. Similarly, it is assumed that when a person lies, his physiological response changes - breathing pattern changes, pulse rate changes, the way one sweats changes, and so on. These physiological changes are used in the polygraph method to detect lies. They ask you questions and electrodes attached to your body record changes in your pulse rates, breathing rate, blood pressure and other things. They compare changes or lack of changes when you lie or do not lie. The lying is found out by asking two types of questions. One type is called control questions. Control questions are very simple, e.g., what is your name? Controlled questions are those for which true answers are already known. You are not expected to have any major detectable or recordable physiological change. Then there is another type of questions, which are called relevant questions. These are questions that are relevant to the investigation of crime or, what they call, specific event investigation. And, if there are changes in the pattern of your physiological responses to such questions, they assume that those changes have a direct association with your psychological state, not just in general, but in particular whether you are lying or telling truth. [21] 

Now is this a scientific proof of whether someone is telling the truth or lying? There is no scientific evidence that the pattern of such association between the psychological state and the physiological response provides us definite information on lying or truth-telling. So the results cannot be said to be hundred per cent true.

There is another device which is similar to the polygraph. It is a hi-tech device called the Computer Voice Test Recorder. It is used a lot in US. In this method, a voice recorder is attached to a computer having certain specialized programmes and functions. Like physiological changes recorded in the polygraph, this device records changes in voice, which is supposed to have a different character when one is lying contrary to when one is telling the truth. The sophisticated computer eventually pronounces whether the person was lying in response to the relevant questions. The judgments in US on the use of this device have shown that these devices too are not fool-proof and they have erred in many cases thereby leading to acquittals. [22] 

Scientific investigation techniques are criticized on the ground that it is not cent per cent accurate. It has been found that certain subjects have made totally false statements. It has also been found that a person has given false information even after administration of drug. These techniques are not of much help in case of malingers or evasive, untruthful persons and moreover, like in case of Narco Analysis, it is very difficult to suggest a correct dose of drug for a particular person. The dose of drug will differ according to will power, mental attitude and physique of the subject. For the success of these scientific techniques a competent and skilled interviewer is required who is trained in putting recent and successful questions. [23] 



The criminal justice system is based on the principle that "let hundred guilty go unpunished than an innocent being punished". To uphold this principle, scientific investigation methods have to be made compulsory in cases where the interest of public at large is involved. For this purpose, it is necessary to amend existing laws and enact new laws so that fair justice is delivered.

Since law is a living process which changes according to the changes in society, science, culture and ethics, the legal system should also change and imbibe scientific developments as long as they do not violate the fundamental legal principles and are for the common good of the society. The criminal justice system should be based on just and equitable principles. The issue of using scientific tests as a tool of interrogation and investigation has been widely debated in India. The extent to which it is accepted in our legal system and our society is something, which will be clearer in the near future. In a situation where Narco Analysis, Brain Mapping, DNA test are sometimes gaining judicial acceptances and supports despite being an 'unreliable and doubtful', we have to seriously rethink about its legal and constitutional validity from human rights perspective.

There has always been a search by investigating agencies for an effective method of interrogation because right from the historical times man has tried to obtain information from an uncooperative source. For obtaining information police have been using physical coercion. In such scenario, these techniques have emerged as a developed tool of investigation.

There is a unanimity that medical and forensic evidence plays a crucial role in helping the courts of law to arrive at logical conclusions. Therefore, the expert medical professionals should be encouraged to undertake medico legal work and simultaneously the atmosphere in courts should be congenial to the medical witness. This attains utmost importance looking at the outcome of the case, since if good experts avoid court attendance, less objective professionals will fill the gap, ultimately affecting the justice. The need to involve more and more professionals in expert testimony has been felt by different organizations. This objective of greater expert participation can only be achieved by addressing to the apprehensions that ponder the mind of medical professionals. In the light of new developments in the forensic science, the Home Ministry of the Government of India constituted a committee under the chairmanship of Dr. Justice V.S. Malimath (which subsequently came to be known as the Malimath Committee) to suggest reforms in the criminal justice system. This committee suggested comprehensive use of forensic science in crime investigation. According to the committee, DNA experts should be included in the list of experts given in Section 293(4) of the Code of Criminal Procedure, 1973.

Scientific methods of investigations are an aid to the interrogators and investigating officers, and they should resort to their use when all else has failed. The police officers should be sensitive to their use and should fully understand the physical, emotional and legal implication of conducting the lie-detector test and administering the truth serum.

In present scenario criminals are getting clever and technical day-by-day. They are making full use of scientific techniques to commit crimes and escape from detection. It has become hard to apprehend and prosecute criminals because the evidence is not readily available. In such a scenario, it will be highly undesirable in the interests of justice that law enforcement agencies are not allowed to make use of scientific evidence, to bring the guilty to the book, due to some confusing legal technicalities.

We should not ignore the positive aspects of such methods. The most significant being that it can be used to determine the innocence of the suspect quite effectively which is one of the main concerns of criminal justice system. Further, where other evidence is not available, evidence through these techniques can be readily be found. In fact these should be admissible in the largest sense of good of society.

Adequate safeguards are required before acceptance of such evidence. Laboratories should have proper quality control and their findings should be fool-proof. Accused should be given opportunity to examine and challenge the authenticity of the test and report. The court may accept such evidence depending upon the authenticity of the source, satisfaction of having followed the established scientific procedure and correctness of the finding. An expert may help the court with his knowledge, skill, experience, training or education to form an opinion or otherwise. The views of the experts based upon scientific method also need to be relevant to the facts in issue and must be scientifically valid, free from errors and accepted by scientific community.

A specific and comprehensive law on the admissibility of scientific techniques will settle the uncertainty regarding the admissibility. However, such law has to be framed with verifying all the scientific and legal aspects, diligently by the experts in both the fields. Now, there is a detailed judgment [24] of the Supreme Court of India to this point. The court has banned Lie Detector test, Narco Analysis and Brain Mapping test. The judgment is viewed as a blow to the investigative agencies which have been restrained from "intruding" into an individual's personal liberty. The court has upheld and endorsed the age-old and time tested dictums, thereby guaranteeing the right of the accused to make a choice between remaining silent and speaking i.e. protection against self incrimination.

With the latest ban on these scientific techniques investigating agencies have suffered a blow in expeditiously reaching out the truth. However, keeping in view the self incriminating nature of this kind of evidence and consequences of employing these two on individual's liberty, the court said in this judgment [25] that it will not only restore people's faith in the judicial system but also enhance all right thinking citizen's respect for human rights and values. [26] 


AIR - All India Reporter

BomCR - Bombay Crime Reporter

CalLT - Calcutta law Times

CriLJ - Criminal Law Journal

DNA - Deoxyribonucleic Acid

HC - High Court

KarLJ - Karnataka Law Journal

KLT - Kerala Law Times

SCC - Supreme Court Cases

US - United States