“Expert Testimony Is Advisory, Not Substantive—Conviction Must Rest on Reliable, Legally Admissible Evidence - Medical Expert’s Opinion Cannot Replace Legal Proof of Guilt,” Rules Supreme Court

Medical Evidence Alone Cannot Prove Guilt—Supreme Court Sets Boundaries for Expert and Circumstantial Evidence in Murder TrialsSupreme Court in sharply delineated the limits of medical and expert evidence in criminal prosecution, overturning a conviction that was anchored almost exclusively on the testimony of a doctor and the accused’s own conduct. The bench of Justice J.B. Pardiwala and Justice R. Mahadevan held that “an accused cannot be held guilty of murder solely on the basis of medical evidence; expert opinion is only advisory and must be supported by other reliable and legally admissible evidence.”

Case Hinged on Postmortem Evidence Amid Hostile Witnesses

The prosecution’s case faced repeated setbacks: nearly all panch and eyewitnesses turned hostile, and the “discovery” of articles allegedly at the accused’s instance was not proved as per law. The courts below, however, relied heavily on the postmortem report and the testimony of Dr. R.K. Divya (PW-10), who conducted the autopsy and opined that the death was homicidal and caused by injuries consistent with a knife.

Despite these weaknesses, both the Trial Court and the High Court accepted the medical opinion as clinching evidence of the appellant’s guilt, further buttressed by the accused’s conduct (pointing out the body and articles) and the confessional FIR.

Supreme Court on the Role of Medical and Expert Evidence:

“A doctor is not a witness of fact. An expert is examined by the prosecution for the purpose of proving the contents of the post-mortem report… The evidence of such an expert is of an advisory character. The credibility of the expert depends on the reasons provided in support of his conclusions, as well as the data and material forming the basis of those conclusions. An accused cannot be held guilty of the offence of murder solely on the basis of medical evidence on record.”

The Court highlighted that the advisory nature of expert evidence means it must be weighed with other direct or circumstantial proof. In the absence of corroboration from independent, substantive evidence, medical testimony cannot become the sole basis for conviction—especially for an offence as grave as murder.

On Discovery Evidence and Section 27, Indian Evidence Act:

The judgment is equally critical of how the prosecution relied on “discovery” evidence under Section 27 and the accused’s conduct under Section 8:

“Most of the panch witnesses turned hostile… If at all, the public prosecutor wanted to prove the contents of the panchnamas after the panch witnesses turned hostile, he could have done so through the investigating officer. However, the investigating officer also failed to prove the contents of the panchnamas in accordance with law. Thus, there is nothing on record by way of evidence relating to any discovery of fact… In other words, no discovery of fact at the instance of the appellant, relevant and admissible under Section 27, has been established.”

“While the conduct of an accused may be relevant under Section 8… it cannot, by itself, serve as the sole basis for conviction, especially for a grave charge such as murder. Like any other piece of evidence, the conduct of the accused is merely one of the circumstances the court may consider, in conjunction with other direct or circumstantial evidence on record.”

Supreme Court’s Caution: “Medical Evidence Is Not Substantive Proof of Guilt”

The Court delivered a crucial reminder for trial courts across India:

“Conviction of the appellant is based on the evidence of Dr. R.K. Divya (PW-10), who has conducted postmortem… It is clear that it is the appellant herein who on the fateful date and time has caused grievous injuries to the deceased, due to which he died. As such, the learned trial Court has rightly held that it is the appellant/accused who has caused injuries over the body of the deceased and caused his death. Accordingly, we hereby affirm the said finding.”

The Supreme Court categorically disagreed with this approach, making it clear that even the clearest medical testimony can at most establish the manner and cause of death—not the identity or culpability of the accused. The ultimate burden is on the prosecution to prove, by legally admissible and direct evidence, the accused’s involvement in the crime.

Conviction Set Aside, Acquittal Ordered

Summing up, the Supreme Court allowed the appeal and acquitted Narayan Yadav, warning that no conviction can be sustained solely on the strength of medical or circumstantial evidence, or on the conduct of the accused in the absence of other reliable evidence.

“The appellant is acquitted of all the charges, and he be set free forthwith if not required in any other case.”

Date of Decision: 05.08.2025