Section 39 BSA: Opinions of Experts

Section 39 BSA explains when expert opinions on science, foreign law, handwriting, fingerprints and electronic evidence are relevant in court.

Introduction

Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 (BSA) deals with the admissibility and relevance of expert opinions when a court must decide questions requiring specialised knowledge. Courts regularly encounter issues involving medical science, forensic evidence, handwriting, fingerprints, foreign law and digital records that may require assistance from a qualified expert.

An expert is a person specially skilled in the relevant subject who provides an opinion to assist the court in understanding technical or specialised matters. The court considers the expert’s qualifications, methods, reasoning and supporting material when assessing the opinion.

For example, where the prosecution alleges that a person died from poisoning, a qualified forensic expert’s opinion about the symptoms and effects of the suspected poison may help the court evaluate the medical evidence.

Section 39 corresponds principally to Section 45 of the Indian Evidence Act, 1872. It also incorporates the rule concerning the Examiner of Electronic Evidence that was previously contained in Section 45A of the former Act.

Bare Act: Section 39 of the Bharatiya Sakshya Adhiniyam, 2023

39. Opinions of experts.

(1) When the Court has to form an opinion upon a point of foreign law or of science or art, or any other field, 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 any other field, or in questions as to identity of handwriting or finger impressions are relevant facts and such persons are called experts.

Illustrations.

(a) The question is, whether the death of A was caused by poison. The opinions of experts as to the symptoms produced by the poison by which A is supposed to have died, are relevant.

(b) The question is, whether A, at the time of doing a certain act, was, by reason of unsoundness of mind, incapable of knowing the nature of the act, or that he was doing what was either wrong or contrary to law.

The opinions of experts upon the question whether the symptoms exhibited by A commonly show unsoundness of mind, and whether such unsoundness of mind usually renders persons incapable of knowing the nature of the acts which they do, or of knowing that what they do is either wrong or contrary to law, are relevant.

(c) The question is, whether a certain document was written by A. Another document is produced which is proved or admitted to have been written by A. The opinions of experts on the question whether the two documents were written by the same person or by different persons, are relevant.

(2) When in a proceeding, the court has to form an opinion on any matter relating to any information transmitted or stored in any computer resource or any other electronic or digital form, the opinion of the Examiner of Electronic Evidence referred to in section 79A of the Information Technology Act, 2000 (21 of 2000), is a relevant fact.

Explanation.— For the purposes of this sub-section, an Examiner of Electronic Evidence shall be an expert.

Meaning and Explanation of Section 39 BSA

Section 39 makes expert opinions relevant when the court must form an opinion on a specialised matter. The provision recognises that certain questions cannot be evaluated properly without knowledge of a particular technical or professional field.

The section has two main parts:

• Subsection (1): Covers opinions concerning foreign law, science, art, other specialised fields, handwriting and fingerprints.
• Subsection (2): Specifically addresses opinions of the Examiner of Electronic Evidence under Section 79A of the Information Technology Act, 2000, concerning information transmitted or stored in computer resources or other electronic or digital forms.

The section does not mean that every opinion expressed by a person claiming expertise is automatically admissible or reliable. The person must possess the relevant specialised knowledge, and the opinion must concern a matter on which expert assistance is relevant.

Essential Elements of Section 39 BSA

1. The court must face a specialised question

Expert opinion becomes relevant when the court must form an opinion on a matter requiring specialised knowledge.

Examples include determining the cause of death, interpreting forensic findings, examining disputed handwriting or understanding digital evidence.

2. The person must be specially skilled in the relevant field

The expert must have appropriate knowledge, training, experience or other relevant qualifications in the subject on which the opinion is offered.

The necessary expertise depends on the issue. A medical expert may assist with a medical question, while a forensic document examiner may assist with the comparison of handwriting.

3. The opinion must concern the relevant specialised issue

The opinion must assist the court in deciding the particular question before it. Expertise in one subject does not automatically qualify a person to express an expert opinion on an unrelated subject.

For example, a medical qualification does not by itself establish expertise in forensic handwriting analysis.

4. Expert opinion is relevant evidence, not an automatic determination

Section 39 makes qualifying expert opinions relevant facts. It does not require the court to accept every expert conclusion.

The court must independently assess the opinion alongside the other evidence, including the expert’s reasoning, the reliability of the methods used and any weaknesses exposed during cross-examination.

5. Electronic evidence receives specific statutory recognition

Subsection (2) expressly recognises the opinion of the Examiner of Electronic Evidence referred to in Section 79A of the Information Technology Act, 2000.

The explanation clarifies that such an examiner is an expert for the purposes of the subsection.

This provision is particularly important in cases involving digital files, electronic communications, computer data and other electronically stored or transmitted information.

Types of Expert Opinions Covered by Section 39 BSA

1. Opinion on foreign law

When the court must form an opinion about the law of another country, a person specially skilled in that foreign law may provide relevant expert evidence.

Example: A dispute concerns the legal effect of a marriage or contract under the law of another country. A suitably qualified expert on that country’s law may assist the court in understanding the relevant legal rules.

Expert opinion on foreign law is different from expert opinion on Indian law, which courts ordinarily determine by applying the relevant Indian legal authorities.

2. Opinion on science

Scientific questions may arise in criminal and civil proceedings. A court may require expert assistance to understand scientific principles, testing methods or forensic findings.

Also Read: Section 45 BSA: Grounds of Opinion, When Relevant

Examples include:

• Toxicology and suspected poisoning.
• DNA analysis and biological samples.
• Medical findings concerning injuries or cause of death.
• Ballistics and firearm examination.
• Chemical analysis of substances.
• Digital and forensic examination of electronic data.

Example: If the prosecution alleges that a victim died from a particular poison, a forensic expert may explain whether the symptoms and test results are consistent with that substance.

3. Opinion on art or another specialised field

Section 39 uses broad language covering science, art and “any other field.” The relevant inquiry is whether the matter requires specialised knowledge and whether the person is specially skilled in that subject.

Example: A dispute involving the authenticity or technical characteristics of a specialised artistic work may require an appropriately qualified expert’s opinion.

The court must assess whether the person’s expertise is relevant to the particular question.

4. Opinion on handwriting

Handwriting experts may compare a disputed document with a document whose authorship is proved or admitted.

The comparison may consider characteristics such as letter formation, spacing, pen movement, slant and other features relevant to the examination.

Example: A party alleges that a disputed signature on an agreement was not made by the person named in the document. A handwriting expert may compare it with admitted or proved specimens.

An expert opinion may assist the court, but the court must consider the quality of the comparison and the other evidence before reaching a conclusion.

5. Opinion on fingerprints

Fingerprint experts may compare impressions found at a scene or on an object with known prints to assess whether they correspond to the same person.

Example: A fingerprint recovered from an object is compared with the fingerprint impression of a suspect. The expert’s opinion may help the court assess the identification evidence.

The value of the opinion depends on the quality of the impressions, the method used and the reliability of the analysis.

6. Opinion of the Examiner of Electronic Evidence

Subsection (2) specifically recognises the opinion of the Examiner of Electronic Evidence referred to in Section 79A of the Information Technology Act, 2000.

This is relevant where the court must form an opinion about information transmitted or stored in a computer resource or another electronic or digital form.

Example: A dispute concerns whether a digital file has been altered or whether particular electronic data can be recovered from a device. An appropriately qualified electronic evidence examiner may provide technical assistance.

However, Section 39 does not make every digital record automatically admissible. The applicable rules governing the proof and admissibility of electronic records, including Sections 61–63 BSA where relevant, must also be considered.

Explanation of the Statutory Illustrations

Illustration (a): Death allegedly caused by poison

Facts: The court must determine whether A’s death was caused by poison.

Application: Experts may explain the symptoms associated with the suspected poison and whether the observed symptoms are consistent with its effects.

Legal principle: Expert medical or scientific opinion is relevant when the cause of death requires specialised knowledge.

Illustration (b): Unsoundness of mind

Facts: The court must determine whether A, at the time of an act, was incapable of understanding the nature of the act or that it was wrong or contrary to law because of unsoundness of mind.

Application: An expert may explain whether the symptoms exhibited by A commonly indicate unsoundness of mind and whether such a condition may affect the person’s capacity to understand the act.

Legal principle: Expert evidence may assist the court in evaluating a mental condition and its possible effect on the capacity relevant to the legal issue. The ultimate legal determination remains with the court.

Illustration (c): Identity of handwriting

Facts: The court must determine whether a particular document was written by A. Another document, proved or admitted to have been written by A, is available for comparison.

Application: A handwriting expert may compare the disputed document with the proved or admitted specimen.

Legal principle: Expert comparison of handwriting is relevant when the authorship of a document is disputed.

Is Expert Opinion Binding on the Court?

No. Expert opinion is generally advisory in nature. Section 39 makes the opinion relevant, but it does not transfer the judicial function from the court to the expert.

The court should examine:

• The expert’s qualifications and relevant experience.
• The material supplied to the expert.
• The scientific or technical method used.
• The reasoning supporting the conclusion.
• Whether the opinion is consistent with the proved facts.
• Any limitations, inconsistencies or alternative explanations.
• The answers given by the expert during cross-examination.

An opinion that merely states a conclusion without explaining its basis may carry less weight than an opinion supported by a clear methodology and reliable material.

Important Judgments Relating to Section 39 BSA

The following decisions interpret Section 45 or related provisions of the former Indian Evidence Act, 1872. They remain relevant to understanding Section 39 BSA, but they were not direct interpretations of the new provision.

1. State of H.P. v. Jai Lal (1999)

Citation: (1999) 7 SCC 280

Court: Supreme Court of India

The Supreme Court explained the nature and role of expert evidence. It observed that an expert is a person specially skilled in the relevant field and that expert evidence assists the court in forming an opinion on technical matters.

Also Read: Section 3 – Evidence may be given of facts in issue and relevant facts – BSA 2023

The Court also emphasised that an expert must provide a reasoned opinion supported by the material on which it is based. The expert’s role is to assist the court, not to replace the court’s judgment.

Legal principle: Expert opinion is advisory. Its evidentiary value depends on the reasons supporting it, the expert’s qualifications and the reliability of the material and methods used.

This is a leading judgment for understanding the weight to be given to expert opinions under Section 39 BSA.

2. State (Through CBI/New Delhi) v. S.J. Choudhary (1996)

Citation: (1996) 2 SCC 428

Court: Supreme Court of India

The case concerned the identification of typewriting and the scope of expert evidence under Section 45 of the former Indian Evidence Act.

The Court considered whether expertise relating to typewriters and their use could fall within the scientific or technical fields recognised by the provision. It adopted a broad approach to the expressions “science” and “art” rather than restricting them to a narrow list of subjects.

Legal principle: Expert opinion may be relevant in a specialised technical field even where the subject is not expressly named in the statutory list, provided the issue falls within the provision and the person is specially skilled in that field.

This principle is relevant to Section 39 BSA, which expressly includes opinions on “any other field.”

3. Selvi v. State of Karnataka (2010)

Citation: (2010) 7 SCC 263

Court: Supreme Court of India

The Supreme Court considered the constitutional implications of involuntary administration of narco-analysis, polygraph and brain electrical activation profile tests.

The Court held that the involuntary administration of these techniques violated the protections under Article 20(3) and Article 21 of the Constitution. It also addressed the evidentiary use of the results of such tests and the restrictions governing the use of information obtained from them.

Legal principle: The relevance of expert or scientific techniques does not override constitutional protections. Scientific testing must comply with the applicable constitutional and legal requirements.

This case is important when studying the limits on the use of scientific evidence in criminal proceedings. It interpreted the former legal framework, including Section 45 of the Evidence Act, rather than Section 39 BSA directly.

4. Ramesh Chandra Agrawal v. Regency Hospital Ltd. (2009)

Citation: (2009) 9 SCC 709

Court: Supreme Court of India

The Supreme Court considered the role of expert evidence in medical negligence litigation. It explained that expert evidence assists the court on technical matters that fall outside ordinary judicial knowledge.

The decision discussed the importance of relevant expertise and the need to assess the opinion in light of the facts and materials available.

Legal principle: Expert evidence is intended to assist the court in resolving specialised questions. Its value depends on the quality and reliability of the opinion, and the court must independently evaluate the evidence.

This judgment is useful for understanding the role of medical experts and the general principles governing expert testimony.

Difference Between Section 39 and Section 40 BSA

Basis	Section 39 BSA	Section 40 BSA
Main subject	Opinions of experts	Facts bearing upon opinions of experts
Focus	Whether a specialised opinion is relevant	Facts that support or undermine the expert opinion
Examples	Medical, scientific, handwriting and electronic evidence	Relevant observations, test results or circumstances affecting the opinion’s reliability
Purpose	Allows expert opinion to assist the court	Helps the court evaluate the basis and weight of the opinion

Section 39 establishes when expert opinions are relevant. Section 40 addresses facts that may support, explain or affect the assessment of an expert’s opinion.

Section 39 BSA and Section 45 of the Indian Evidence Act, 1872

Basis	Section 39 BSA	Section 45, Indian Evidence Act
Subject	Opinions of experts	Opinions of experts
Foreign law	Covered	Covered
Science and art	Covered	Covered
Handwriting and fingerprints	Covered	Covered
Other specialised fields	Expressly refers to “any other field”	Did not use the same express phrase in its original wording
Electronic evidence examiner	Included in subsection (2)	The corresponding provision was later inserted as Section 45A
Current status	In force from 1 July 2024	Repealed, subject to applicable savings provisions

Section 39 BSA substantially carries forward Section 45 of the former Evidence Act while incorporating the specific rule concerning the Examiner of Electronic Evidence that was previously contained in Section 45A.

Related Legal Provisions

• Section 40 BSA: Facts bearing upon opinions of experts.
• Section 41 BSA: Opinion as to handwriting and signature, when relevant.
• Section 45 BSA: Grounds of opinion, when relevant.
• Section 61 BSA: Electronic or digital record.
• Section 62 BSA: Special provisions as to evidence relating to electronic records.
• Section 63 BSA: Admissibility of electronic records.
• Section 79A, Information Technology Act, 2000: Provides for the Examiner of Electronic Evidence referenced in Section 39(2) BSA.
• Article 20(3), Constitution of India: Protects an accused person against compelled self-incrimination and is relevant to the constitutional limits discussed in Selvi v. State of Karnataka.

Important Points for Law Students and Judiciary Exams

• Section 39 BSA corresponds principally to Section 45 of the Indian Evidence Act, 1872.
• It covers opinions on foreign law, science, art, other specialised fields, handwriting and fingerprints.
• Subsection (2) specifically recognises the opinion of the Examiner of Electronic Evidence under Section 79A of the Information Technology Act, 2000.
• An expert must be specially skilled in the relevant field.
• Expert opinion is relevant but is not automatically binding on the court.
• The court must assess the expert’s qualifications, methods, reasons and supporting material.
• The three statutory illustrations concern poisoning, unsoundness of mind and handwriting comparison.
• State of H.P. v. Jai Lal explains the advisory role of expert evidence.
• Selvi v. State of Karnataka establishes constitutional limits on involuntary scientific investigative techniques.
• Section 39 must be distinguished from Section 40, which concerns facts bearing upon expert opinions.

Frequently Asked Questions (FAQs)

1. What is Section 39 of the BSA?

Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 makes expert opinions relevant when the court must form an opinion on foreign law, science, art, another specialised field, handwriting, fingerprints or specified electronic and digital matters.

2. Which section of the Indian Evidence Act corresponds to Section 39 BSA?

Section 39 BSA corresponds principally to Section 45 of the Indian Evidence Act, 1872. Its subsection (2) incorporates the rule concerning the Examiner of Electronic Evidence previously contained in Section 45A of the former Act.

3. Is expert opinion binding on the court?

No. Expert opinion assists the court but does not determine the case automatically. The court must independently evaluate the expert’s qualifications, reasoning, methodology and supporting evidence.

4. Who qualifies as an expert under Section 39 BSA?

An expert is a person specially skilled in the particular subject on which an opinion is required. Relevant qualifications, training, knowledge and experience may establish the person’s expertise.

5. Is a handwriting expert’s opinion relevant under Section 39?

Yes. Section 39 expressly recognises expert opinions concerning the identity of handwriting and finger impressions. Such opinions may assist the court when authorship or identity is disputed.

6. What is the role of the Examiner of Electronic Evidence?

Under Section 39(2), the opinion of the Examiner of Electronic Evidence referred to in Section 79A of the Information Technology Act, 2000 is a relevant fact when the court must form an opinion about information transmitted or stored in a computer resource or another electronic or digital form.

7. Can the court reject an expert’s opinion?

Yes. The court may reject or give limited weight to an expert opinion if its reasoning, methodology, qualifications or supporting material are inadequate or inconsistent with the other evidence.

8. What is the difference between Sections 39 and 40 BSA?

Section 39 deals with the relevance of expert opinions. Section 40 deals with facts bearing upon those opinions, which may help the court assess their reliability and evidentiary weight.

Conclusion

Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 enables courts to consider specialised opinions when deciding technical questions that require knowledge beyond ordinary judicial experience. It covers foreign law, science, art, other specialised fields, handwriting, fingerprints and specified electronic evidence. However, expert opinion is an aid to judicial decision-making rather than a substitute for it. The court must assess the expert’s qualifications, reasoning, methodology and supporting material before deciding what weight the opinion deserves.