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by Nidhi Tandon*

Cite as : (2004) 8 SCC (J) 17


The vigilant search for truth is the hallmark of our criminal justice system. Our methods of investigation, rules of criminal procedure and appellate process are designed to ensure that the guilty are punished while the innocent are protected. However, while ours is a system to be cherished, it is not a perfect system, and those charged with the administration of justice have a responsibility to seek its continued improvement.

Science and law, two distinct professions have increasingly become commingled, for ensuring a fair process and to see that justice is done. The legal system today, has to deal with novel scientific evidence on several occasions, which has posed profound challenges for the law. At a basic level, many of these challenges arise from fundamental differences between the legal and scientific processes. The dilemmas are self-evident. On one hand, scientific evidence holds out the tempting possibility of extremely accurate fact-finding and a reduction in the uncertainty that often accompanies legal decision-making. At the same time, scientific methodologies often include risks of uncertainty that the legal system is unwilling to tolerate.

Moreover, at every instance, scientific evidence tests the abilities of judges and lawyers, all of whom may lack the scientific expertise to comprehend the evidence and evaluate it in an informed manner. Lawyers must attempt to comprehend the complexity of scientific analysis and terminology if they are to fully understand testing procedures and results, and their impact in the legal arena. One recent development in the scientific community that has had a substantial and almost mesmerizing impact on the legal profession—is the development of deoxyribonucleic acid (DNA) profiling1 in criminal cases.

Scientific technology now enables forensic investigators to identify individuals from their DNA sequence. This technique compares the genetic pattern contained in the body cells of one human with the genetic pattern of the body cells in another. Realising this immense potential of DNA evidence, countries in the West have already developed a jurisprudence of both academic and practical might, and have begun to utilize this technique frequently for resolving complicated cases. India seems to be lagging behind considering that our courts are sceptical and uncertain about appreciating scientific evidence of such strong impact on the outcome of a trial. If the process of DNA bar code analysis receives continued judicial acceptance, it would constitute the single greatest advancement of India's criminal law courts towards the goal of convicting the guilty and acquitting the innocent.

Scientific evidence, as experienced in the past, can produce dynamic changes in the course of trial, but they are nothing in comparison to the twists and turns which DNA evidence produces. In every trial, where DNA evidence is adduced, the court has to be alert and extremely careful in placing reliance on it. DNA evidence can open up a Pandora's box generating controversial issues ranging from admissibility and appreciation to privacy and confidentiality. Further, there is concern expressed over situations where new-found evidence or newly introduced tests can lead to the exculpation of previously convicted offenders in respect of the same crime in issue. In such post-conviction exculpations, there is a live debate regarding its practicality and its legitimacy in the light of criminal justice administration.

Expert testimony and the courts

It is an ancient rule of the common law that on a subject requiring special knowledge and competence, evidence is admissible from witnesses who have acquired, by study or practice, the necessary expertise on the subject.2 Such witnesses are known as "experts". The evidence is justified by the fact that the court would be unable, unaided, to draw proper inferences and form proper opinions from such specialized facts as were proved before it.

The foundation on which expert evidence rests is the supposed superior knowledge or experience of the expert in relation to the subject-matter upon which he is permitted to give an opinion as evidence. This not only enables them to form opinions and to draw inferences from observed facts, but also to identify facts, which may be obscure or invisible to a lay witness. In State of H.P. v. Jai Lal3 the Supreme Court opined that an expert witness is one who made the subject upon which he speaks a matter of particular study, practice, or observation and he must have a special knowledge of the subject. In order to bring the evidence of a witness as that of an expert it has to be shown that he has made a special study of the subject or acquired a special experience therein.4 From anyone else such statements would be inadmissible. However, the evidence of an expert is merely of an advisory character. An expert is not a witness of fact.

The duty of an expert witness is to furnish the judge with the necessary scientific criteria for testing the accuracy of the conclusions so as to enable the judge to form his independent judgment by the application of these criteria to the facts of the case. The credibility of such a witness depends on the reasons stated in support of his conclusions and the data and material furnished that form the basis of his conclusions.

Expert opinion evidence may be contradicted and cross-examined, like any other evidence. The position of an expert is that he must be regarded as any other independent witness, and although he enjoys such weight as may follow from his peculiar ability to assist the court, it will be a misdirection to direct the jury that his evidence could be accepted unless the witness himself betrays reasons for rejecting it. There will be occasions where the evidence may have to be rejected on procedural grounds and occasions where the court will have to choose between conflicting opinions from experts dealing with the same matters.

At common law, the expert is not asked to give his opinion on the "ultimate question", or in other words, to give his opinion on an issue in the case. The reason was that he would thereby usurp the functioning of the court. Thus, the witness might describe to the court the mental condition of the accused, but might not be asked whether the accused was insane if that was the issue, which the court had to decide upon.5 In the case of DNA evidence, the above distinction will be brought out in the fact that whether a match between the DNA samples was found or not and will not determine the real fact in issue which is whether that particular person committed that particular offence or not. Though DNA evidence, if admitted will be relied upon to the extent that it is used to corroborate other evidence that is available to the judge for reaching a particular conclusion, of acquitting or convicting the accused. To that end, DNA evidence will be an important piece of corroborative evidence and not conclusive proof.

Novelty of DNA evidence: need for expert testimony

Forensic science is experiencing a period of rapid change, in the wake of the dramatic evolution of DNA profiling. The air of triumphalism here is extraordinary: it is the triumph of reaction against progress and is also the exemplification of the chasm between law and science.6 DNA has entered the vocabulary of the man on the street,7 perhaps not so much because of the beautiful work of those such as Watson and Crick8 as more because of the dramatic impact DNA profiling has had on crime detection.

Many will share the view that DNA profiling is the greatest advance in forensic science since the acceptance of fingerprint identifications by the courts at the turn of the century. The question often asked of a DNA profile is "Is it as good as a fingerprint?" Like many apparently simple questions, it does not have as simple an answer, and gives us an opportunity to reflect on a fascinating paradox.

The important difference between fingerprint identification and DNA profiling is that the former has not been derived from a coherent body of data and statistical reasoning, while the latter has. This has led to a fundamental difference between the ways that the two kinds of evidence are presented at court.9 When fingerprint identification is presented the expert will state that he or she is certain that a particular crime mark was made by the originator of a given exemplar print. The weight of a DNA profiling match, however, will be presented by means of a numerical statement—typically a "match probability".10

DNA: The unstoppable witness

Your DNA sequence is unique amongst all DNA sequences of any human that has ever lived and will live for quite some time to come. Unless you have an identical twin, in which case you do have someone who has the same DNA sequence. But apart from that, your DNA sequence is yours and yours alone.

Thus is born the notion of DNA identification. And it was quickly realised that this DNA identification would be especially useful in legal cases, in the criminal courts.11 In some senses, DNA provides a genetic "future diary" about a person's life, because it contains information about significant future events, such as susceptibility to disease and possibly, about behavioural traits. It may also contain information, which the person has chosen to keep secret (about sexual orientation, for example).

Major applications in criminal law *

First, it assists in positively identifying perpetrators of crime, particularly in cases of sexual assault and homicide, where identification is often a central issue.12 *

Second, and perhaps a corollary of the other applications, DNA analysis can exculpate wrongly accused suspects. *

Third, DNA tests can identify the remains of victims of violent crimes.13

Before the DNA test results are obtained and applied, the legal framework in which DNA samples are obtained needs to be considered. Two issues arise here. What powers do the police already enjoy in this respect and what implications might the technique hold for police powers in the future. Given the powers of search and seizure14 as described under the Criminal Procedure Code, 1973, the police are restricted in the use of their powers and are required to respect the fundamental and human rights of the individuals and follow a fair and reasonable procedure while obtaining samples as evidence. However, the following three yardsticks can be kept in mind while carrying out crucial investigation:

(1) The nature of the offence—how serious is it?

(2) The nature of the test—how intrusive is it?

(3) The nature of the evidence obtained—how probative is it?

The police comprise the primary investigative body that assists the prosecution's case. All evidence collected by them is used to strengthen the case for conviction. For DNA analysis, they have been empowered to collect samples they think necessary for testing and accordingly send the same to the sole DNA testing laboratory in India at the Centre for Cellular and Molecular Biology (CCMB) at Hyderabad. Police officers and other investigators of the crime scene often have a limited understanding of how to collect, store and transport DNA evidence. Under financial constraints police are faced with making informal cost-benefit estimates before proceeding to collect DNA evidence. There are also very large financial interests in the success of the test, and their continued application by the courts. The people carrying out the tests have a vested institutional interest in prosecutions being successful.

At present, the access to resources for adducing DNA evidence in court remains restricted to the prosecution and it is very rare that the defence introduces DNA evidence. Furthermore, with the police forces having a substantial control over evidence presented to CCMB for testing, the independence and the correctness of the results is doubted. Under strong pressure from the prosecution to attain conviction, the police may often compel a specific result from the laboratory. This certainly questions the veracity of DNA evidence and brings to the fore the human element involved in proving such exclusive knowledge to the court, where one may become victim to temptation and give in to economic strains. When experts come for a price, nothing much can be said about the procedure involved, the evidence falls flat, being a mere concoction, tampered to a side's advantage.

However, before we step into the ethical and social dilemmas of DNA evidence, we must understand how such evidence is collected. The police have been vested with certain powers in this respect. They can collect various samples from the accused, the victim, the site of the offence and other related material objects, etc. The samples thereby collected can be classified as follows:

1. Intimate samples: defined as "a sample of blood, semen or any other tissue, fluid, urine, saliva or pubic hair, or a swab taken from a person's body orifice".

2. A non-intimate sample means:

"(a) a sample of hair other than pubic hair,

(b) a sample taken from a nail or under a nail,

(c) a swab taken from any part of a person's body other than a body orifice,

(d) a footprint or similar impression of any part of a person's body other than a part of his hand."15

DNA sampling has already proved itself to be of prime importance in the detection of certain categories of offences, especially those associated with violence. However, certain safeguards should be observed. Firstly a caution should be administered and legal advice offered. Secondly, an independent third party should be present to observe the sampling should the suspect wish and preferably the whole procedure be videotaped. Thirdly, the sampling should be carried out in the circumstances of maximum privacy and when possible by qualified personnel. Fourthly, the suspect should be provided with a portion of the sample for his own analysis. Finally, stricter rules should be enforced about the storage and destruction of samples.

The scientific processes involved

To comprehend the technique of DNA fingerprinting, we must thoroughly understand its fundamental scientific processes. The most prevalent form is termed "DNA fingerprinting," which requires forensic scientists to prepare a DNA sample from a bodily fluid such as blood or semen. They proceed by creating a "fingerprint", which appears as a fragment of bands. In general, DNA fingerprinting is a laboratory procedure that requires isolation of DNA, cutting, sizing and sorting, transfer of DNA to nylon, probing, etc.16

However, a good deal of doubt is there as regards the veracity of the process, because of the nature of the technique and the scope for human error involved. The sample obtained could well have come into contact with a lot of other substances and hence as a result of reactions could have altered its chemical structure. Besides, when the enzyme is applied it cuts the DNA sample at a lot of different places thereby creating more bands that will appear on the autoradiograph. In fact there are a lot of other serious scientific doubts that are there as regards the whole process, which require a detailed look at the science involved that is too technical and beyond the scope of this article.17

Over the years, the technology has undergone rapid change and refinement that has increased both its capability to obtain meaningful results from old evidence samples and its discriminatory capabilities. At first, crime laboratories relied primarily on restriction fragment length polymorphism (RFLP) testing,18 a technique that required a comparatively large quantity of good-quality DNA. Now, however, most laboratories are shifting to using tests based on the polymerase chain reaction (PCR) method,19 a kind of molecular copying technique that can generate reliable data from extremely small amounts of DNA in crime scene samples.

PCR can actually amplify a DNA sequence a millionfold, thereby generating enough DNA to study and identify the guilty individual. The problem is that small amounts of contamination could produce confusing or incorrect results. If one piece of DNA gets amplified a millionfold then a similar contaminating DNA would also be amplified a millionfold and the results would be hard to interpret.20

Problems with DNA sampling

First about which little is known is degradation. Very often, the source of DNA from the scene of the crime has been exposed to various chemical actions.21 If the source is blood, then the sample would have undergone chemical and physical change by efflux of time, it may have come into contact with other substances and thereby undergone chemical change.

The second is at the stage of the preparation of the sample and the application of the chemical scissors, the restriction enzyme used to cut the DNA into manageable fragments cuts the DNA at too many places. Each extra fragment would create an extra "band" on the autoradiograph. Thus, two samples from the same source would produce different "pictures" on the autoradiograph.22 This would cast doubts on whether there is a "true" pictographic representation of DNA structure at all!

Further grounds of attack stem from the frailties of judgment in the visual inspection of bands from two profiles. A match is declared when two bands, one from each profile, are within a 'bin" i.e. the two bands are within a specific distance of each other on the autoradiograph. The assumption is that a little variance is allowed so that a particular fragment may not produce a band in the same place always.

These hazards would demolish any hope of sustainability of DNA evidence. In the event that a match continues to be confirmed, the significance of the match still needs to be established by calculating the match probability for which the frequency with which the alleles23 represented in the autoradiograph occur within a population.24 The question is always what the chances are that there could have been another person who could have generated the same sample, which was the basis of the test.

Pitfalls of population genetics

The evidentiary and probative value of DNA profiling is reliant on the fact that the probability of a random match of the sample found on the victim, to those of the accused is extremely low. The probabilities are calculated using the results of population studies. For the population to be in some sort of equilibrium, the population must be large, there must be no selective matting, there must be no mutation of genes, there must be no interpopulation exchange of genetic material i.e. no migration/immigration and there must be no natural selection with regard to one genetic type.25 The probability of a cosmopolitan city population meeting the above criteria is extremely low.

To determine the significance of a match, the probability of occurrence of a match within a particular community must be known. This requires an elaborate empirical database of population characteristics to be able to narrow down the accused. A likelihood ratio could be used to balance any similarities between two profiles against the dissimilarities. Statisticians have used the Baye's Theorem26 to calculate conditional probabilities. The likelihood ratios so arrived at could be expressed in terms of weight of evidence. At the end of the day, the procedure, the statistical techniques used to determine the match probability and the appreciation of the evidence as a whole leaves one in doubt whether one is dealing with objective science at all.27

After the above description of DNA analysis, it is obvious that setting universal standards for forensic applications of DNA testing is the most controversial and unsettled issue. To date, little agreement exists as to who should decide, what standards are best, and how to achieve and implement them.

DNA evidence in the dock

The ultimate objective of evidence in a criminal case is to convince the judge or jury of the prosecution or defence's contention. Evidence, from which inferences of relevant facts may be drawn, such as the scientific analysis of an individual's DNA bar code pattern, is a subcategory of circumstantial evidence. The admission of expert/scientific evidence in a criminal trial is not that dissimilar from any other evidence, namely, that the evidence is relevant and has probative value. Technically the rule of admissibility of expert evidence is usually stated in its negative form, as an exception to the inadmissibility of evidence of opinion as opposed to fact.

In the case of People v. Castro28 the New York Court noted that a three-pronged test needed to be followed in determining whether the DNA evidence adduced should be admitted:

1. Is there a theory, which is generally accepted in the scientific community, which supports the conclusion that DNA forensic testing can produce reliable results?

2. Are there techniques of experiments that currently exist that are capable of producing reliable results in DNA identification and which are generally accepted in the scientific community?

3. Did the testing laboratory perform the accepted scientific techniques in analysing the forensic samples in that case?

The truth is that, whatever the test which is applied, the question whether expert evidence derived from a novel scientific technique is to be admitted is one to answer which a trial court operating within the adversarial system is wholly inappropriate. There are three major reasons for this.

First, in an adversarial process, the question of resources immediately falls for consideration. Secondly, the determination is not like other findings of fact. It is quite as much, if not more legislative as any other decision on a matter of law, but since it must be treated as a holding of fact, it has no generalised application holding by one trial court that a particular scientific technique does or does not satisfy a particular test is by way of a preliminary finding of fact by the judge. Precisely the same expert witnesses could be lined up and give the same testimony only for the second judge to take the opposite view. This leads to very serious objections on the grounds of legality, predictability and length of proceedings. Thirdly, there is a question whether judges are qualified to make this sort of decision. It may be said that within the common law tradition it is for the parties to inform the judge, and that to properly establish the probative potential of any science this might involve calling epistemologists, in addition to practitioners of the science in question.

It is, therefore important that the DNA profiling process is understood, at least in outline, and that the manner in which the evidence should and should not be used at trial is made as clear as possible to counsel and expert witnesses. If scientists adopt novel and empirically unsupported techniques of calculation the evidence may be rejected as insufficiently reliable as demonstrated in CBI v. Santosh Kumar Singh.29

Admissibility, burden and weight

During a trial the proponent of the evidence meets the burden of establishing that the DNA analysis performed in the present case provides a trustworthy and reliable method of identifying characteristics in an individual's genetic material. Additionally, if the evidence is admissible, issues questioning the reliability of test procedures may attack the weight of the evidence.30 The party preferring the forensic DNA evidence will have the affirmative burden of showing the following:

(a) the acquisition of the sample,

(b) the chain of custody of the sample and test results,

(c) the proper labelling of samples,

(d) the testing procedures followed, and

(e) the interpretation of the test results by a scientist properly qualified to read and interpret the test results.

Much of the discussion depends for its value upon there being adequate means by which to show departures to have been made from established procedures. If no effective monitoring takes place, or if the defence does not have a full description of the manner in which the tests are carried out, it does not really matter what provisions are made for the exclusion of evidence. The quandary that a trial Judge faces dealing with DNA evidence is not if the burden of proof on the prosecution stands discharged, but whether the evidence meets the standard of proof required to convict viz. beyond reasonable doubt in a criminal trial. Considering the brooding uncertainty and scope for error, one is persuaded to wait and watch. At best, its contemporary use is in eliminating suspects.

The Indian perspective

DNA technology in course of time is bound to play a prominent role in our legal system in both the criminal and civil areas giving a new look to the subject of expert testimony. In the matters of fixing the paternity and maternity of a child and also in cases of homicide and rape, DNA fingerprinting evidence will be a decisive and clinching factor. In India, barring a negligible number, cases have yet to come before the courts involving expert opinion in the science of DNA technology.

In a case that came before the Court of Chief Judicial Magistrate, Tellicherry (Kerala), one Vilasini a village girl, filed a petition against one Kunhiraman for maintenance alleging that a child was born to her on account of the illicit connection between them.31 The defendant disowned her and denied the paternity of the child. The Chief Judicial Magistrate ordered both of them to undergo DNA fingerprinting test in order to ascertain the parentage of the child at CCMB, Hyderabad, which is carrying out experiments in this field. As Kunhiraman had no identical twin brother, the court safely arrived at the conclusion that he was the biological father of the child.

In the recently concluded case of CBI v. Santosh Kumar Singh31 DNA evidence was sought to prove that the deceased had been raped. The defence submitted that it was a malicious attempt to connect the accused with the DNA profile. The so-called DNA profile was found suspicious and shrouded in mystery.

There could have been a possibility of tampering with the samples32 that were sent for DNA testing. The burden was on the State as to show that the samples had not been tampered with. It was submitted that the underwear of the accused was tampered with and semen was planted upon the same. Unfortunately for CBI and fortunately for the accused the DNA laboratory returned the said underwear without analysis considering the same to be irrelevant.

The Court, however, stated that the State in the matter of DNA identification evidence must satisfy that the physical evidence upon which the test was conducted has been obtained in accordance with law and reached the laboratory without being interfered with.33 Due procedure and protocol was applied and that the accused got due opportunity of fair hearing in the matter of analysis and during trial.

It was submitted, questioning the DNA report of CCMB, Hyderabad, that proper procedure for the examinations of the exhibits had not been adopted. The opinion of the expert in view of Section 45 of the Indian Evidence Act34 was held to be admissible provided the validity of the underlined protocol of the analysis was established. The validity of the technique applying those principles on a particular occasion had to be established. Further, in carrying out the analysis, the expert should have recorded the observation of analysis in such a manner as to give due opportunity of rebutting the opinion given by the experts. The DNA evidence adduced in the case was held inadmissible and was rejected.

The problem with DNA results is apparent—making them meaningful to a judge.35 The judge can also fall into the trap of confusing the probability of sample identification with a probability of guilt due to various factors. It is most unusual for a judge to be trained in anything other than the law, and as such to be grappling with issues that are often technical and obscure, shrouded in language that lawyers assert is designed to complicate and confuse, adds to the difficulty of the task.

DNA evidence, no doubt has the ability to increase the accuracy of verdicts in criminal trials. But this does not mean that we should be complacent about its use and presentation. With the human genome almost being mapped to completion, the discovery of the constituents of the human DNA will create a comprehensive database eventually resulting in a human databank of DNA publicly accessible and tremendously utilised in criminal investigations.

DNA evidence and the privilege against self-incrimination

The discovery of genetic fingerprinting with its high specificity and extraordinary probative properties highlights the question of the scope of the privilege against self-incrimination. The fact that the public would probably see DNA fingerprinting as harder to fabricate, as more objective than a verbal statement, it may also mean it is more difficult for the individual to refuse and for his refusal to be seen as legitimate. Fear, anxiety, embarrassment, and anger, rather than guilt, may account for non-cooperation in supplying a bodily sample just as they may account for silence. The suspect may be apprehensive regarding how the test is conducted and more importantly, how accurate it is, especially if he does not understand what the test involves or lacks confidence in the testing procedures and controls.

The question that now comes to mind is whether or not it is legal for the courts to ask the accused to supply a sample of his DNA for the analysis. What is of concern here is that does forcing the accused to provide a sample of his DNA amount to a violation of the protection against self-incrimination? Also, if the accused refuses to give the sample then does that mean that an adverse inference will be drawn against him?

In the case of Goutam Kundu v. State of W.B.36 there was a question of disputed paternity. The Court held, 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. The constitutionality in taking a fingerprint was challenged in the case of State of Bombay v. Kathi Kalu Oghad.37 The Supreme Court held that Article 20(3)38 of the Constitution gives protection to a person not to be a witness against himself. However, "to be a witness" is not equivalent to "furnishing evidence" in its widest term and significance. Giving thumb or finger impression or exhibiting parts of the body by way of identification are not included in the expression "to be a witness". Being a witness has been interpreted to mean imparting some sort of knowledge in testimony. From this it appears that there will be no constitutional restriction on the collection of samples for DNA analysis.39

The dilemma of DNA databases

The creation and use of the DNA database raise a number of criminal justice issues. The development of DNA databanking poses an invasion of civil liberties, particularly "fundamental justice" rights (the taking of samples without laying a foundation of reasonable and probable grounds). Since DNA can reveal more than identity alone "privacy" will also become an issue.

Today, there are many instances where you have to release personal and medical information about yourself. This happens when you apply for a job, for life or health insurance, for credit, for financial aid, or for benefits from the Government. If the results of any DNA tests become part of your records, you may have to release the information in order to obtain needed services. Right now, there are no laws concerning DNA databanks.

Databanks take one of three possible forms. The least comprehensive databank would comprise samples of convicted persons. At the opposite end, a much broader databank would consist of DNA profiles obtained by routine testing of inhabitants of an area where a crime has been committed. It is also claimed that area or national testing would benefit innocent persons by providing a means by which they could be eliminated from police inquiries.

An objection to databanks of all descriptions is that the information contained in the samples obtained is more compendious than is required for the purposes of criminal investigation. Unlike a fingerprint the sample obtained for the purposes of a DNA profile may reveal not only whether X was at the scene of the crime, but also whether X has any genetic defects or diseases, such as AIDS. The uses to which this superfluous information might be put raises important civil rights questions. Aside from the principled objections above, national testing appears to lack cost-effectiveness.

It has been suggested that DNA profiles contain data of such a personal nature that they should not be stored on databases.40 At first, this claim seems credible. DNA contains personal information, and when people have access to personal information about us, which we have not chosen to reveal to them, our privacy is infringed. Owing to such concerns, samples must be destroyed once profiles have been obtained from them. This would certainly be an appropriate solution to the problem of multiple uses.

Convicted by juries, exonerated by science: post-conviction exculpation

Through the use of DNA evidence, prosecutors are often able to conclusively establish the guilt of a defendant. At the same time, DNA aids the search for truth by exonerating the innocent. The advent of DNA testing raises the question of whether a different balance should be struck regarding the right to post-conviction relief.

A convicted individual's continued assertion of innocence is not new to the criminal justice system and in fact is familiar to appeal courts. The use of DNA technology may bring to courtroom proceedings a degree of certitude to which neither the defence nor the prosecution is accustomed. Typically, in an appeal, the possibility that the original verdict will be overturned is merely suggested. By contrast, the introduction of DNA evidence after conviction may definitively prove innocence.

The typical inmate making a post-conviction DNA request, would want: (1) discovery of the evidence so that it can be tested, (2) the right to present favourable test results in a judicial proceeding or in an executive proceeding for clemency, and (3) the State to pay for the testing. At this point, the law in many jurisdictions is not clear as to the legal theory that entitles the petitioner to have any of these requests granted, or what the appropriate procedural mechanisms are for making these demands. Frequently, these issues are intertwined, and petitioners make omnibus motions in which they raise all potentially relevant grounds for relief together.

Because of this present state of legal uncertainty, litigating post-conviction DNA applications often will be unnecessarily complex, expensive and time-consuming. Also, exploring the effect that DNA technology may have on the statutes of limitation for filing appeals and charges. The latter issue arises because DNA samples last indefinitely, beyond the periods of time permitted for such filings.41

Moreover, this process has little validity in India, where conviction on the basis of DNA evidence itself is difficult to obtain. The current justice administration does not provide for any post-conviction relief, considering the facts that it is an extra expense on the State machinery requiring a retrial over the same issues, lack of manpower and lack of legal and medical expertise dealing with DNA.

Conclusion: so near, yet so far

Improved testing technologies are ensuring more efficient DNA evidence processing. Advances in technology and databanking promise to widen the use of DNA evidence as an investigational tool. As laboratories improve their ability to process DNA evidence quickly, and as the courts' expectations of the use of DNA test results increase, there will be greater emphasis on initial collection of evidence at the crime scene. Nevertheless, we are still far from full realisation of the potential of DNA testing.

Initial collection of evidence is a key link in the chain of events leading to successful testing, but it is also a vulnerable link. Currently the groundwork is being prepared to strengthen specimen collection and preservation, with more structured crime scene teams and more formalised evidence collection procedures being established in many jurisdictions. The aim of these terms is to ensure that all potential evidence is recovered and properly preserved for testing, and especially to minimise the possibility of contamination.42 There will also be a greater stress for court-driven expert opinion, where the judge when he thinks fit, can send suitable material for testing. This would reduce tampering of evidence and also the inherent bias that exists in favour of the prosecution.

On the face of it this evidential avenue seems to offer great promise for the avoidance of miscarriages of justice. On the one hand, it avoids several human fallibilities, such as memories or responses affected by fright or lapse of time or self-condemnatory statements induced by disorientation or undue pressure. On the other hand, it calls in aid the wonders of modern science with its allure of cold detachment and technical probity and precision.

In the wake of the Priyadarshini Matoo case in which, on closer scrutiny, the prosecution's scientific evidence was found wanting, DNA evidence has been labelled as potentially unreliable. The problem is deep-seated as evident in this miscarriage of justice, to have occurred because DNA evidence adduced at the trial was not properly tested or understood. Apart from the enormous task of empirically calculating the probabilities, given the diverse substructures within the Indian polity, there is also need to reduce possibilities of tampering with evidence. This can be done by setting up of authorised laboratories, which would be accountable directly to the courts.

Moreover, sensitisation and education of the judges and the investigative personnel to the process, method and manner of DNA analysis is important to make the entire procedure more efficient and reliable. Simultaneously the veil of ignorance amongst the common man must be lifted as to the role that DNA can play in the never-ending pursuit for justice and truth.

These are the fundamentals in which the legal system must facilitate DNA evidence in court. Rather than leave it to a case-by-case approach of the courts, legislation is the need of the hour. The only caution that needs to be kept in mind is that law cannot sway to the tune of science and nor can the law or legal jurisprudence isolate itself from the rationality and practical understanding science can provide in order to resolve the problem at hand. How long it takes before DNA evidence can be universally accepted as a piece of reliable evidence, depends primarily on us, the legal and scientific fraternity to develop a standard for adducing such evidence in court. Until then, DNA evidence will not be silenced by disagreements on protocol, method, admissibility and other hindrances. The DNA "witness" is unstoppable, give it a chance and it will speak the truth and only the truth.


* BA, LLB (Hons), National Law School of India University. Return to Text
1 Throughout this article, the terms DNA fingerprinting, DNA profiling and DNA typing have been used interchangeably. They have the same connotation, the only difference lying in the fact that every new procedure of testing DNA used a term specific and subjective to that testing process. Return to Text
2 As long ago as the mid-sixteenth century, Justice Saunders expressed the readiness of the law to accept guidance from qualified experts when in Buckley v. Rice Thomas, (1554) 1 Plowden 118 he exclaimed that it is an honourable and commendable thing in our law to apply for the aid of science or faculty. Return to Text
3 (1999) 7 SCC 280 Return to Text
4 It has also been held that a photographer with 25 years' experience in the line could well give expert evidence, even though he had not obtained a degree or diploma in the subject. In the 1960s-70s, there were only two handwriting experts in India, both form Himachal Pradesh and without any particular qualification in the study of handwriting. They had built their expertise on the basis of the experience they acquired over the years. Return to Text
5 Peter Murphy, Murphy on Evidence, 5th Edn., pp. 304-06 (London: Blackstone Press Ltd., 1995). Return to Text
6 Ian W. Evett, et al, "DNA Profiling: A Discussion of Issues Relating to the Reporting of Very Small Match Probabilities", 2000 Cri LR 341. Return to Text
7 O.J. Simpson's trial was one in which the court utilised the testimony of an expert to verify the DNA evidence adduced by the prosecution. Return to Text
8 The structure of the DNA was first described by Watson and Crick in "Molecular Structure of Nucleic Acid: A Structure for Deoxyribose Nucleic Acid": (1953) 171 Nature 737. As the chemical dispatcher of genetic information, DNA's structure resembles a twisted ladder, referred to as a double helix. DNA in all organisms consists, in part, of four chemical subunits commonly called bases. These four bases—guanine (G), adenine (A), thymine (T), and cytosine (C)—are the genetic alphabet. Their unique order, or sequence in the DNA helix serves as the blueprint for an organism. Of the 3.3 billion base pairs making up a human blueprint, only a fraction, about 3 million differ between any two individuals. DNA is found in all body cells except red blood cells. With a few exceptions, the composition of a person's DNA does not vary from cell to cell, except in egg and sperm cells, which have half the complement of DNA present in other body cells. The segment that does vary among individuals is known as restriction fragment length polymorphisms (RFLP). Scientists measure DNA size distinctions between people through the RFLP process. Another technology often used is the polymerase chain reaction (PCR), which is like "molecular photocopying". Return to Text
9 Moreover, if there are two contradictory opinions of fingerprint experts, then the value of the opinions will be diminished. Corroboration always adds weight to the value whereas contradiction decreases evidential significance of the opinion. See Dr. S.S. Sharma, "Fingerprint Science and its Evidential Significance", 1995 Cri LJ 91. Return to Text
10 K.F. Kelly, et al., "Methods and Applications of DNA Fingerprinting: A Guide for the Non-Scientist" 1987 Cri LR 105. Return to Text
11 DNA evidence is also put to many other uses such as: * To identify relatives * To prove fatherhood * To identify bodies: DNA typing has helped identify numerous murder and accident victims. * To identify soldiers: Blood and saliva samples are taken from new recruits and stored. If that soldier dies in combat and the body is too damaged to identify, DNA from the body can be compared to the DNA in the stored samples. DNA typing was first used to identify soldiers killed in the Gulf War. * To uncover history: Examining the DNA of people long dead, revealing information about the past. * To study human evolution. Return to Text
12 It is harder to use DNA as evidence to convict a person because juries need to find the defendant guilty "beyond a reasonable doubt". There also is the chance that someone "planted" the DNA to pin the crime on the accused or that the testing lab has made a mistake. However, testing labs have improved their procedures to reduce the risk of false matches. Return to Text
13 Simon J. Young, "DNA Evidence—Beyond Reasonable Doubt?", 1991 Cri LR 264. Return to Text
14 See Sections 93-103 of the Criminal Procedure Code, 1973, provisions relating to search and seizure. Return to Text
15 See Clive Walker and Ian Cram, "DNA Profiling and Police Powers", 1990 Cri LR 479. Return to Text
16 For a more detailed description see generally: Kristopher Kubon, "The Technology behind the conviction: DNA Fingerprinting", Illunim, www.usc.edn/dept/enginneering/illunim/vol3issue 3/dna/page5.html, visited on July 14, 2004 Return to Text
17 See generally, Simon J. Young, "DNA Evidence—Beyond Reasonable Doubt?", 1991 Cri LR 264 and Peter Allridge, "Recognizing Novel Scientific Techniques: DNA as a Test Case", 1992 Crim LR, 687. Return to Text
18 The use of restriction fragment length polymorphism testing (RFLP testing) in human DNA identification was pioneered by Professor Sir Alec Jeffreys and first reported in 1985: (1985) 315 Nature 76. Since then, RFLP testing has been widely used for determination of biological relationships, post-conviction relief cases, etc. RFLP testing generally requires a sample containing DNA that is not degraded from 100,000 or more cells (e.g. a dime-sized or larger saturated bloodstain). The procedure for RFLP testing requires that DNA isolated from a biological sample be cut into smaller fragments using a protein called a restriction enzyme. The DNA fragments are then separated based on their relative length and the DNA fragment size variations among different individuals are determined using DNA probes specific for discrete locations in the human genome. These results are generally visualized as a series of bands on films. The relative position and number of the bands obtained from an evidentiary sample are compared to those obtained from known individuals for the determination of exclusion or inclusion. Return to Text
19 Polymerase chain reaction (PCR) testing of nuclear DNA was developed by Dr Kary Mullis at Cetus Corporation in 1984 and has rapidly become the most widely used technique in the field of molecular biology. PCR testing of nuclear DNA may be done on a wide variety of samples that are quite small, containing 50 to 100 cells or more (e.g. visible dot of blood, a single hair root). PCR is the test method of choice for samples that contain DNA that is degraded (e.g. pathology specimens, samples that have been improperly stored or are aged). The PCR test process consists of three basic steps: (1) the preparation of DNA in a sample for testing, (2) the amplification (or copying) of specific regions of the DNA, and (3) the analysis or readout of the test results. Return to Text
20 See http// (June 20, 2000). Return to Text
21 Environmental conditions such as heat, humidity and ultraviolet light, the substrate (the surface upon which the biological evidence is found), are all factors that should be considered when measuring the integrity of a DNA forensic analysis. As far as the age of the biological evidence is concerned, successful DNA bar code tests have been done on blood and semen stains five years old. DNA in a wet bloodstain will start to degrade in two days and in a semen stain will start to degrade within a week. Return to Text
22 Ricardo G. Federico, "The Genetic Witness: DNA Evidence and Canada's Criminal Law", (1990-91) 33 CLQ 206. Return to Text
23 Allele is the name given to the alternative forms of a particular gene, only one of which can be present in a chromosome. Return to Text
24 Murali Neelkantan, "DNA Testing as Evidence: A Judge's Nightmare", Law and Medicine, 80 (1996). Return to Text
25 Supra fn 13. Return to Text
26 In the late eighteenth century, Thomas Bayes described his famous theorem about conditional probability: P (A/B) = P (B/A) P (A)/ P (B). In other words, the probability of some event A occurring given that event B has occurred is equal to the probability of event B occurring given that event A has occurred, multiplied by the probability of event A occurring and divided by the probability of event B occurring. Baye's theorem is the fundamental mathematical law governing the process of logical inference, determining what degree of confidence we may have, in various possible conclusions, based on the body of evidence available. Return to Text
27 Supra fn 25. Return to Text
28 545 NYS 2d 985 (Sup 1989) Return to Text
29 FIR No. 50 of 1996 in the Court of the Additional Sessions Judge, New Delhi. Return to Text
30 James Virgil Harvey, "Acquit or Convict: Should Profile DNA be Conclusive?" http://www/ (July 20, 2000). Return to Text
31 Dr V. Krishnamachari, "DNA Fingerprinting Evidence and its Legal Admissibility", 1994 Cri LJ (Journal Section) 1. Return to Text
32 For DNA testing the objects analysed were: (1) the blood of the accused, (2) the vaginal swab/smear of the deceased, (3) the clothes of the deceased. The semen of the accused on the underwear, which the accused was allegedly wearing at the time of the alleged offence, was not checked by the DNA laboratory. The underwear was returned without analysis considering the same to be irrelevant (a blatant mistake). Return to Text
33 The State has to satisfy the following: (1) Obtaining known/unknown biological samples in accordance with law. (2) The State must establish a proper chain of custody for the substance subjected to the analysis. A proper foundation connecting the evidence to the accused or to place or object should be established. (3) Laboratory procedure, protocol and quality control. (4) Fair hearing is to be resorted to. Return to Text
34 Section 45 of the Indian Evidence Act, 1872, states: "45. 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 opinions upon that point of persons specially skilled in such foreign law, science or art, or in questions as to identity of handwriting or finger impressions are relevant facts. Such persons are called experts." Return to Text
35 The judges, being people without detailed scientific training, may often be impressed by an expert's qualifications, appointments and experience and the confident manner in which he expresses his opinion. It should not be left to such matters alone to provide a foundation for the judge making an assessment of the probative value of the forensic evidence, particularly where there are conflicts in expert testimony, or where it is acknowledged that other experts of more or less equal distinctions are unlikely to agree. Return to Text
36 (1993) 3 SCC 418 Return to Text
37 AIR 1961 SC 1808 Return to Text
38 Article 20(3) of the Constitution states: "20. (3) No person accused of any offence shall be compelled to be a witness against himself." The constitutional validity of this section was examined in the case of Kathi Kalu Oghad, AIR 1961 SC 1808. The Supreme Court decided that asking the accused to provide a thumb impression does not amount to a violation of the protection as provided by Article 20(3) of the Constitution. It is submitted that the same logic can be extended to cover these areas also. Return to Text
39 State of Bombay v. Kathi Kalu Oghad, AIR 1961 SC 1808 Return to Text
40 Mike Redmayne, "The DNA Database: Civil Liberty and Evidentiary Issues", 1998 Cri LR 437. Return to Text
41 This restrictive approach rests on: 1. The strong presumption that the verdict is correct because the accused was found guilty by a jury of peers after a trial conducted with full constitutional protections. 2. The need for finality. 3. The recognition that the likelihood of more accurate determinations of guilt or innocence diminishes over time as memories fade, witnesses disappear and the opportunity for perjury increases. 4. The need to conserve judicial resources by not opening the floodgates to meritless and costly claims. Return to Text
42 Like, for example, the preparation of medical kits for the purposes of investigating sexual offence and unnatural deaths. Similar kits could also be prepared with a detailed procedure elaborated for the collection of important forensic evidence including that of DNA and properly conserved for testing. The possibility of contamination and tampering are the most important concerns in such cases and precautions must be taken in order to avoid the same.

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