Evidentiary value of Expert opinion

Bharatiya Sakshya Adhiniyam, 2023

TANMOY MUKHERJEE INSTITUTE OF JURIDICAL SCIENCE

Dr. Tanmoy Mukherjee

[Advocate]

 

Evidentiary value of Expert opinion

Tanmoy Mukherjee

[Advocate]

 

Relevant Sections-

Section 39(1)BSA [Section 45 IEA]	Opinions of experts (foreign law, science, art, handwriting, finger impressions)
Section 39(2)BSA [Section 45A IEA]	Opinion of Examiner of Electronic Evidence.
Section 40 BSA [Section 46 IEA]	Facts supporting/rebutting expert opinion may be proved.
Section 41 BSA [Section 47 IEA]	Opinion as to handwriting by persons acquainted with it.
Section 45 BSA [Section 51 IEA]	Grounds of opinion to be proved.

 

Nature of Expert Opinion-

1.Advisory in character- It guides, not dictates the court.

2.Not substantive evidence- Unlike eyewitness testimony, it is only corroborative.

3.Court is not bound- Judges can accept or reject expert advice.

4.Weak type of evidence- Needs corroboration by direct/circumstantial evidence.

5.Reliability depends on method and credibility- Opinion based on guesswork has no value.

Judicial Pronouncements-

 

-Ram Chandra v. State of U.P. (AIR 1957 SC 381)

Expert evidence is a weak type of evidence, must be corroborated.

-Magan Bihari Lal v. S.O Punjab (AIR 1977 SC 1091)

Handwriting expert's opinion alone is unsafe for conviction.

-Murari Lal v. State of M.P. (AIR 1980 SC 531)

Court may rely on handwriting expert's opinion if corroborated by other evidence.

-Piara Singh v. State of Punjab (AIR 1977 SC 2274)

Fingerprint expert's evidence is admissible and has greater reliability than handwriting, but still not conclusive.

-Ishwari Prasad Misra v. Mohammad Isa (AIR 1963 SC 1728)

Opinion of handwriting expert is only an opinion, not conclusive proof.

-State of H.P. v. Jai Lal (AIR 1999 SC 3318)

Expert evidence is advisory; court must evaluate it carefully before acceptance.

-Ramesh Chandra Agrawal v. Regency Hospital Ltd. (2009) 9 SCC 709

Expert opinion is not binding; it only assists the court in forming an independent judgement.

-Selvi v. S.O. Karnataka (2010) 7 SCC 263

Narco-analysis, polygraph, brain mapping cannot be solely relied on; they violate Art 20(3). Their evidentiary value is limited.

-S.O. Maharashtra v. Damu (2000) 6 SCC 269

DNA evidence is highly reliable but still must be corroborated.

-Santosh Kumar Singh v. State (2010) 9 SCC 747

DNA and medical expert opinion helped corroborate circumstantial evidence, leading to conviction.

-S. Gopal Reddy v. State of A.P. (1996) 4 SCC 596

Expert opinion under Sec. 45 IEA is only a piece of evidence; not conclusive.

-Malay Kumar Ganguly v. Sukumar Mukherjee (2009)

In medical negligence, expert evidence is relevant but not final; court must apply its own reasoning.

-Thogorami @ K. Damayanti v. State of Orissa (2004 Cr.L.J 4003, Ori HC)

Scientific expert opinion has weight but is not substantive evidence; must be tested against other facts.

Types of Expert Opinions & their value-

Type of Expert	Section	Case law	Evidentiary value
Handwriting Expert	39(1) (BSA) EA)	-Magan Bihari Lal (1977) - Ishwari Prasad (1963)	Weak, unsafe if sole basis.
Fingerprint expert	39(1) (BSA) (45 IEA)	Piara Singh (1977)	Stronger than handwriting, still needs support.
Medical expert	39(1) (BSA) (45 IEA)	- Malay Kumar Ganguly (2009) - Ram Narain (AIR 1975)	Helps determine cause of death/injury; corroborative.
DNA expert	39(1) (BSA) (45 IEA)	- State of Maharashtra v. Damu (2000) - Santosh Kumar Singh (2010)	High accuracy but corroboration preferred.
Electronic Evidence Expert	39(2) (BSA) (45A IEA)	Anvar P.V. v. P.K. Basheer (2014) 10 SCC 473	Admissible with Sec. 65B IEA certificate.
Narco/ Polygraph	39(1) BSA [read with Art. 20(3)]. (Sec. 45 IEA [read with Art. 20(3)].	Selvi (2010)	Limited; not conclusive proof.

 

-Expert evidence is relevant (Sec. 39 BSA) (Sec. 45 IEA) but not conclusive.

-It is opinion evidence and cannot override substantive direct evidence.

-Its weight depends on scientific basis, competence of expert, and corroboration.

-Court must apply the rule of caution - sift truth from exaggeration.