Post-Mortem Report and Medical Evidence under the Bharatiya Sakshya Adhiniyam, 2023: Status, Contents, Proof and Limitations

The post-mortem report is produced in every trial for homicide and is relied upon constantly, yet its evidentiary status is among the most misunderstood matters in criminal practice. It is not substantive evidence. It is a record of what a medical officer observed and concluded, and it becomes evidence only when he deposes to it. Understanding what the report contains, what its findings can and cannot establish, and how it must be proved disposes of a large part of the argument in most such trials.

1. What a Post-Mortem Report Is

A post-mortem examination is conducted on the body of a person whose death is unnatural, suspicious or unexplained, on a requisition issued during the inquest. The medical officer examines the body externally and internally and prepares a report of his findings and conclusions.

The report is a contemporaneous record made in the discharge of official duty. That is its strength: it is prepared before any dispute about the manner of death has crystallised, by a person with no interest in the outcome, following a settled procedure. It is also the source of its limitations, because it is a record of observations and inferences, not an account of the occurrence.

2. What the Report Contains

The contents fall into four parts, and the distinction between them governs how each is used.

2.1 Identification and preliminaries

Details identifying the body, the requisition on which the examination was conducted, who identified the body to the medical officer, the date and hour of receipt of the body, and the date and hour of the examination. The interval between death and examination matters, because several of the conclusions depend on it.

2.2 External examination

The general condition of the body; the state of rigor mortis and post-mortem lividity; the temperature; signs of decomposition; and a description of each injury — its nature, situation, dimensions, direction, margins and whether it appears ante-mortem or post-mortem. This is the part of the report on which most argument turns, because it is here that the injuries said to have been inflicted are recorded.

2.3 Internal examination

The findings on dissection — the condition of the skull, brain, thoracic and abdominal organs, the tracks of any penetrating injuries, fractures, haemorrhage, and the condition and contents of the stomach. The stomach contents are recorded because they bear on the interval between the last meal and death, which in turn bears on the time of death.

2.4 Opinion

The medical officer's conclusions — the cause of death, the approximate time since death, the class of weapon that could have produced the injuries, whether the injuries were sufficient in the ordinary course of nature to cause death, and whether death was homicidal, suicidal or accidental so far as the findings permit any view. Where viscera have been preserved for chemical examination, the opinion may be reserved pending that report.

3. The Report Is Not Substantive Evidence

This is the proposition most often stated and least often applied. A post-mortem report is a document. Producing it and marking it as an exhibit does not make its contents evidence of anything. What makes the findings evidence is the testimony of the medical officer, given on oath and subject to cross-examination.

The report itself performs three functions once the medical officer is in the witness box. It refreshes his memory under the provisions relating to refreshing memory, which is essential where he has conducted hundreds of examinations since. It may be used to corroborate his testimony under Section 160, being a statement made at or about the time of the fact. And it may be used by the opposing party to contradict him under Section 148 where his evidence departs from what he recorded.

What follows is that a report exhibited without its author being examined establishes nothing. The findings in it are the untested assertions of a person whose competence has not been established, and no conclusion can be founded on them.

3.1 Where the medical officer cannot be examined

Three routes exist where the author is unavailable, and they are not interchangeable.

The statutory route. The criminal procedure legislation provides that the reports of certain classes of government scientific expert may be used as evidence without the author being called, subject to the court's power to summon him and to examine him if it thinks fit. Where a report falls within that provision, it may be read; where it does not, it may not.

Section 26(b) of the Adhiniyam. Where the medical officer has died, cannot be found, has become incapable of giving evidence, or cannot be produced without unreasonable delay or expense, the report is a statement made by him in the discharge of professional duty, and is relevant under clause (b) of Section 26. The gateway condition of unavailability must be proved, not asserted.

Proof by a successor or a colleague. Where the medical officer has been transferred, retired or died, another medical officer familiar with his handwriting and signature may prove the document under Section 41(1), and may give his own opinion on the recorded findings under Section 39. What such a witness cannot do is depose to the observations, because he did not make them; he can only speak to what conclusions the recorded findings support.

4. The Post-Mortem Report and the Inquest Report

The two documents are prepared at about the same time and are frequently confused. They serve entirely different purposes and have entirely different evidentiary value.

An inquest is held by a police officer or a Magistrate on receiving information that a person has died unnaturally. Its purpose is to ascertain the apparent cause of death and to describe the wounds and marks found on the body, so that a decision can be taken whether a post-mortem examination is required. It is an investigative step, not a fact-finding proceeding about the occurrence.

The practical consequence is important. Defence arguments founded on the absence of the accused's name from the inquest report, or on the absence of a description of the occurrence, do not ordinarily succeed, because the report was never intended to contain those things. What may be significant is a description of the injuries in the inquest report that conflicts with the post-mortem findings, since both purport to describe the same body.

5. The Limitations of Post-Mortem Findings

Four limitations recur, and each has produced a settled body of practice.

5.1 Time since death is an estimate

The indicators — rigor mortis, lividity, cooling, decomposition, the state of the stomach contents — all vary with ambient temperature, humidity, the physical condition and clothing of the deceased, the nature of the last meal and individual physiology. A medical officer who states a time of death as a point rather than a range is overstating what the discipline supports, and one who states a range is doing what he can.

5.2 The weapon is identified by class, not individually

A medical officer can say that an injury was caused by a sharp-edged weapon, a blunt object, a pointed instrument or a firearm at a particular range. He cannot ordinarily say that a particular recovered weapon caused it. Where the weapon is shown to him and he opines that the injury 'could have been caused' by it, that is a statement about class and possibility, and it should not be read as identification.

5.3 Negative findings prove less than they appear to

The absence of a finding is not, without more, evidence that the thing did not occur. The absence of external injury does not exclude internal violence; the absence of injury in a sexual offence does not exclude the offence; the absence of poison in a viscera report may reflect the substance used, the interval, or the method of preservation. In each case the medical officer should be asked what the absence signifies, and the answer is frequently that it signifies less than the party relying on it hopes.

5.4 Sufficiency in the ordinary course of nature

The opinion that an injury was sufficient in the ordinary course of nature to cause death is an ingredient of the graver form of culpable homicide, and it is therefore among the most consequential opinions a medical officer gives. It is an opinion about the injury in the abstract, not about what in fact happened to this deceased, and the distinction is worth pressing in cross-examination — an injury may in fact have caused death without being sufficient in the ordinary course of nature to do so, and the converse is equally possible.

6. The Report and the Rest of the Case

The post-mortem report sits at the centre of a homicide trial and is compared against three other things.

Against the ocular evidence, on the principle that medical evidence is ordinarily corroborative and displaces eyewitness testimony only where it completely rules out the possibility of that testimony being true. This is the comparison examined in the separate treatment of medical and ocular evidence.

Against the recovered weapon, where the question is whether the injuries are consistent with the class of weapon recovered. A positive answer corroborates the recovery; a negative answer is a serious difficulty for the prosecution. Where a firearm is involved, the ballistic expert's evidence connects the weapon to the projectile, and the medical evidence connects the projectile to the injury; both links are needed.

Against the inquest report, where the comparison is confined to the description of the injuries, both documents purporting to describe the same body at about the same time.

A fourth comparison arises where the deceased made a dying declaration. The account of the manner of the attack given in the declaration is tested against the post-mortem findings, and a declaration inconsistent with the medical evidence cannot be acted upon. This is one of the settled infirmities that defeats a dying declaration however voluntary it may have been.

7. Practical Matters

1. Delay in conducting the examination must be explained where it is substantial, since several findings deteriorate with time and the reliability of the estimate of time since death diminishes.
2. The identity of the body must be established. The person who identified the body to the medical officer should be examined, and where the body was decomposed or disfigured, identification becomes a distinct issue requiring its own proof.
3. Preservation and transmission of viscera must be proved where a chemical examination is relied upon, with the same rigour as any other chain of custody. A negative or positive chemical report on a sample that cannot be connected to the body proves nothing.
4. A second post-mortem, where one has been conducted, must be accounted for, and the findings of both placed before the court. Suppressing an earlier report and relying on a later one is a serious matter.
5. The medical officer should be examined on the specific injuries relied upon, and not merely on his conclusions. It is the recorded findings, not the summary opinion, that must be matched against the ocular account.

8. The Position Stated Shortly

1. A post-mortem report is not substantive evidence. The testimony of the medical officer is, and the report refreshes his memory, corroborates him under Section 160, or contradicts him under Section 148.
2. The report contains observations and opinion, and the two are attacked in different ways.
3. Where the author cannot be examined, three routes exist — the statutory provision for reports of government scientific experts, Section 26(b) where he has died, and proof of the document by a successor, which does not prove the observations.
4. The inquest report serves a different purpose — to ascertain the apparent cause of death — and omissions from it are ordinarily immaterial.
5. Time since death is always a range, and a divergence of some hours from the ocular account is not a reasonable doubt.
6. The weapon is identified by class, not individually, and an opinion that an injury 'could have been caused' by a recovered weapon is a statement about possibility.
7. Negative findings prove less than they appear to, and the medical officer should be asked what an absence signifies.
8. Sufficiency in the ordinary course of nature is an opinion about the injury in the abstract, and is distinct from what in fact caused this death.

9. Related Topics and Provisions