This article has been written by Pragya Rakshita, a student of the National University of Study and Research in Law, Ranchi.

Introduction

Usually, under the law of Evidence, third parties, that is, persons who are unacquainted with the facts and circumstances of the case are not called upon to give their testimony, opinion or witness in any criminal trial. This is a general principle of the law of Evidence. The exception to this principle is “Expert Opinion”, where an expert of a particular subject is consulted to give his opinion on the relevant subject and it is relevant in deciding the case, even though he or she is a stranger to the case and is unacquainted with the facts and circumstances of the case.

The first question that comes to mind is who really is considered as an expert. An “Expert”[1] is a person who has-

1. special knowledge 
2. skill, or
3. experience,

in either of the following subjects-

1. foreign law,
2. science,
3. art,
4. handwriting, or
5. finger impression,

and such knowledge has been gathered by him or her through-

1. practice,
2. observation, or
3. proper studies.

Even though the definition derived and interpreted from the statute is only limited to the above mentioned five subjects, in practice the Court may consult experts on some other matters as well. For example, medical practitioners, chemical analysts, explosive experts, fingerprint and handwriting experts etc. are consulted by the Court on matters of expertise.

Expert opinion is not required in all cases, whether criminal or civil. Generally, the opinions of experts are admissible whenever an issue comprises a subject of which knowledge can only be acquired by special training and experience.[2] If the subject matter is such that an inference regarding it can be drawn conveniently, then expert opinion cannot be sought.[3] The subject matter must be such as to require specialized knowledge and only then can expert evidence be sought for. Also, an expert cannot give his opinion suo moto, unless called upon by the Investigating Officer.

Relevant Provisions

The provisions that deal with expert opinion are Sections 45 to 51 and Section 73 of the Indian Evidence Act, 1872.

Section 45 provides that the opinions of third persons are relevant if such third person is an expert who is consulted by the Court on a point of such expertise. Section 45A, which was inserted by the Information Technology (Amendment) Act, 2008, regards an Examiner of Electronic Evidence as an expert and makes his opinion relevant. Section 46 makes such facts relevant which either support or reject the opinion of the expert.

Sections 47 and 47A pertain to opinions regarding the handwriting or signature and electronic signature of a person. Section 47A was inserted by the Information Technology Act, 2000. Also, Section 73 empowers the Court to compel a person to furnish a sample handwriting or signature, and also fingerprints for the purpose of comparison and ascertainment.

Sections 48 and 49 provide that the opinions as to the existence of any right or custom and of any usages or tenets are relevant when such opinion is given by a person who would likely be aware of its existence or have special knowledge about the same. The opinion of a person as to the relationship between two other persons is also relevant, if he has special means of gaining such knowledge, under Section 50.

Section 51 makes the grounds on which such opinion is given as relevant.

Types

There are various types of expert evidence, and many more new methods and mechanisms are being developed and applied everyday with the continuous advancement in science and technology. The currently available expert evidences are divided into the following types[4]:

1. Medical Evidence- This type of expert evidence is given by a medical practitioner and it is conducted in a medical laboratory. These are further subdivided into the following types-

1. Cause of Death in cases alleged to be due to physical violence;
2. Cause of Death in cases alleged to be due to causes other than physical violence;
3. Whether Death was accidental, suicidal or homicidal;
4. To prove Legal Insanity;
5. In cases of Sexual Offences;
6. To determine age;
7. In disputed Paternity cases; and
8. Miscellaneous matters.

2. Non-Medical Evidence- These are the expert evidences other than medical in nature. These are further sub-divided into-

1. Fingerprints;
2. Footprints;
3. Handwriting;
4. Typewriting;
5. Forensic Ballistics;
6. Narco-analysis;
7. Polygraph Test; and
8. Brain Mapping.

These are just some of the methods that are currently practiced in the investigation process in India. Many new methods and techniques are being developed and will soon be in use for the purpose of investigation, but in each method it must be ensured that the rights of the individual are not hampered. In cases where the rights of the accused are affected, the constitutionality of the evidence comes into question, which is further discussed in the next section of this research paper.

Constitutionality

The constitutionality of expert evidence was challenged as against Article 20(3) and Article 21 of the Constitution of India, 1950. The basic contention was that by compelling (which could go to the degree of application of physical force) a person to give sample of his handwriting or signature, or forcing him to go through Narco-analysis, Polygraph Test and Brain Mapping, the Court was compelling a person to self incriminate, which is in violation of Article 20(3) of the Constitution. This whole process was also in violation of a person’s right to life and liberty under Article 21 of the Constitution. Hence, the constitutional validity of the whole process was challenged time and again in the Court.

These questions were addressed by an eleven-judge bench of the Supreme Court in the case of State of Bombay v. Kathi Kalu Oghad[5], where the question was regarding fingerprints and handwriting samples. The Court upheld that compelling the accused to provide fingerprint and handwriting samples under Section 73 for the purpose of expert opinion was not hit Article 20(3), and hence was constitutional. It was discussed in this case that giving samples was not equivalent to being a witness against themselves, as the samples were not evidences per se. Rather, the report made by the expert would be the evidence in this case, and the expert would act as a witness against the accused. Moreover, this case narrowed down the scope of protection under Article 20(3) by stating that the clause “to be a witness” means imparting knowledge about facts of which the person has personal knowledge through oral or written statements, whereas giving specimens of fingerprints or handwriting do not fall under this, as these have an intrinsic and unchangeable nature that is verifiable. So, here, the distinction between “physical” and “testimonial” evidence was maintained.

In another case of Goutam Kundu v. State of West Bengal[6], where there was a question as to paternity, the Supreme Court held that no person can be compelled to give blood sample and any refusal cannot be interpreted adversely.

Then, in the case of Selvi v. State of Karnataka[7], the Supreme Court was again faced with the validity of three specific and extensively used investigation methods of Narco-analysis, Polygraph Tests and Brain Mapping. In Narco-analysis, a truth serum is administered to the subject to ensure that he speaks the truth, whether he is willing or not. In the Polygraph Test and the Brain Mapping methods, the physiological responses to various questions are analyzed to decide whether the subject is speaking the truth or not. In this case, the Supreme Court declared all three of these methods as unconstitutional. The Apex Court emphasized on the distinction between physical privacy and mental privacy. Through these methods, the mental privacy of an accused was encroached upon, hence infringing not only Article 20(3) of the Constitution, but also Article 21. Hence these methods were declared unconstitutional.

Through the daily advancement in science and technology, there are no ends to the methods that are and can be employed in any criminal investigation. With the emergence of new methods, a question is casted upon the sanctity of a person’s privacy and on the principle against self incrimination. Every new method poses a question as to what can and what cannot be permitted to be practiced by the legal investigators so as to achieve the end of justice, while also preserving the fundamental rights of the individual. It seems that the Supreme Court must analyze every new method on the basic guidelines provided in the above judgments.

Once the Court concludes that the expert opinion is admissible, as the expert is qualified enough to be legally considered as an expert, the method used was constitutional, and the procedure through which it was administered was not flawed, then it becomes admissible and the Court can rely on it. Now, the next question before the Court of law is regarding its evidentiary value, that is, till what extent can the Court rely on the opinion of the expert. This question is elaborated upon in the next part of this research paper.

Evidentiary Value

Expert opinion is a rather weak type of evidence and the Courts do not generally consider it as offering conclusive proof, and therefore do not rely solely upon it without seeking independent and reliable corroboration.[8] It is well settled law that the opinion of a handwriting expert cannot be considered as conclusive proof unless substantiated by corroborating evidence.[9]

In the case of Ram Chandra v.  State of U.P.[10], it was held by the Supreme Court that it would be unsafe to treat the opinion of the handwriting expert as sufficient basis for conviction, but it can be relied upon when supported by other items of internal and external evidence. This was again reiterated in Ishwari Prasad Misra v. Mohd. Isa[11], because expert evidence is, after all, only opinion evidence. Hence, it was time and again upheld by the Apex Court that expert evidence, being only opinion evidence, cannot be substantive and conclusive evidence, and cannot be the sole basis of conviction, but it can be relied upon if it is corroborated by other evidence, whether direct or circumstantial.[12] Further, in the case of Alamgir v. NCT of Delhi[13], it was held that though there was no rule of law or prudence that states that opinion evidence must never be acted upon unless substantially corroborated, due caution and care must be exercised and it must be accepted after probe and examination.

In Ram Narain v. State of Uttar Pradesh[14], the kidnapper was convicted solely on the basis of handwriting expert’s opinion by the lower courts and the Supreme Court upheld the conviction while stating that if after comparison of the disputed and admitted writings by the Court itself, it is considered safe to accept the opinion of expert, then the conclusion so arrived at cannot be attacked on special leave merely on the ground that expert opinion is generally considered inconclusive.

In the case of Baso Prasad and Others v. State of Bihar[15], it was held that even though expert opinion is relevant, appreciation of evidence is the Court’s job and hence, it is for the Court to decide which expert opinion to take into consideration in cases of contradicting medical and ballistic opinion.

In Murari Lal v. State of Madhya Pradesh[16], the Supreme Court has laid down the following rules on which the reliability of such opinion has to be tested:

1. There is no rule of law, not any rule of discreet which has crystallized into a rule of law, that the opinion evidence of an expert must never be acted upon, unless substantially corroborated.
2. But, having due regard to the various adverse factors operating in case of expert opinion, the approach should be on caution. Reasons for the opinion must be carefully probed and examined thereto. All other relevant evidence must be considered.
3. In appropriate cases where corroboration must be sought. In cases where the reasons for the opinion are convincing and there is no reliable evidence throwing a doubt, the uncorroborated testimony of an expert may be accepted.
4. The hazard in accepting the expert opinion, is not because experts, in general, are unreliable witnesses, the quality of credibility or incredibility being one which an expert may go wrong because of some defect of perception, or honest mistake conclusion. The more developed and more perfect a science, less is the chance of an incorrect opinion.

The opinion of an expert witness is not considered to be conclusive in nature because there is the danger of error or deliberate falsehood[17]; human judgment is fallible and human knowledge is limited and imperfect[18]; and also because an expert witness, however impartial he may wish to be, is likely to be unconsciously prejudiced in favour of the side which calls him[19].

Evidence of an expert is merely of an advisory character.[20] So, usually expert opinion cannot be the sole basis for conviction and other corroborating evidence must be relied upon, but a conviction cannot be set aside solely on the basis that generally expert evidence is not considered as a conclusive proof. Thus, the Courts must analyze the circumstances of each case, and take decisions from a case to case basis.

Conclusion

Expert evidence is an extensively used method in the investigation process, as with the advancement of technology, it has now become imperative in almost all cases, especially criminal. Whether it is a case of murder, rape, accident, suicide or theft, in all kinds of cases, expert opinion can and is used to strengthen the prosecution case. To be able to successfully use expert opinion, many intricacies need to be considered and be taken care of. First of all, the types of experts that need to be consulted in each case has to be determined. Then, it must be confirmed that the selected methods are constitutional in nature. This is a controversial issue and a grey area in the law of expert evidence. The Supreme Court has attempted to provide some basic guidelines on the basis of which the constitutionality of the expert evidence methods may be analyzed. The kinds of methods in which the accused is only directed to give a sample of his handwriting, signature, fingerprint, DNA and the like, where it does not amount to evidence in itself, but only amounts as a sample, then it cannot be said that the accused is being compelled to be a witness against himself and hence, such methods are constitutional. Whereas, if the methods are such that compel the accused to give certain information of which he has special and exclusive knowledge, then that amounts to compelling him to be a witness against himself and hence, are considered to be unconstitutional. Even after the test of constitutionality is passed, the opinion of the expert is not considered as conclusive proof, and a conviction is usually not solely based on expert opinion.

References

[1] Section 45 of the Indian Evidence Act, 1872.

[2] Law Society of India v. Fertilizers and Chemical Travancore Ltd. & Ors., AIR 1994 Kar 308.

[3] V. Kishan Rao v. Nikhil Super Specialty Hospital & Anr., (2010) 5 SCC 513.

[4] Y.H. Rao & Y.R. Rao, Expert Evidence (Medical & Non-Medical) (4th ed. Reprint 2011).

[5] (1962) 3 SCR 10.

[6] (1993) 3 SCC 418.

[7] (2010) 7 SCC 263.

[8] Magan Bihari Lal v. State of Punjab, AIR 1977 SC 1091.

[9] Siddheswar Prasad Singh v. Baba Sundari Pramanick, AIR 1978 Cal 4.

[10] AIR 1957 SC 381.

[11] AIR 1963 SC 1728.

[12] Shashi Kumar Banerjee v. Subodh Kumar Banerjee, AIR 1964 SC 529; Fakhruddin v. State of M.P., AIR 1967 SC 1326.

[13] (2003) 1 SCC 21.

[14] AIR 1973 SC 2200.

[15] (2006) 13 SCC 65.

[16] AIR 1980 SC 531.

[17] Haryana Seeds Development Corporation Ltd. v. Sadhu, AIR 2005 SC 2023.

[18] Mohd. Zahid v. State of Tamil Nadu, AIR 1999 SC 2416.

[19] Gulzar Ali v. State of Himachal Pradesh, (1998) 2 SCC 192.

[20] Nidhi Tandon, The Journey from One Cell to Another: Role of DNA Evidence, 8 SCC J-17, J-18 (2004).

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