“The Unnatural-Conduct Test” – Supreme Court Re-affirms Strict Scrutiny of Eyewitness Credibility and Restraint in Overturning Acquittals

1. Introduction

In Nimai Ghosh v. State of Bihar now Jharkhand, 2025 INSC 816, the Supreme Court of India revisited two recurring themes in criminal jurisprudence: (1) how appellate courts should treat a trial court’s acquittal, and (2) the extent to which the conduct of purported eyewitnesses affects their credibility. The case sprang from the alleged broad-daylight murder of one Manmohan Ghosh in 1989, witnessed, according to the prosecution, by his own son and two nephews. Although the Trial Court acquitted all six accused for want of credible evidence, the Jharkhand High Court – 23 years later – convicted three of them, prompting the present criminal appeal.

2. Summary of the Judgment

The Supreme Court (J.K. Maheshwari & Aravind Kumar, JJ.) set aside the High Court’s judgment and restored the trial court’s acquittal on these grounds:

The behaviour of the three eyewitnesses (close relatives of the deceased) was “absolutely unnatural” – they neither attempted to save the deceased, nor immediately informed police or family, choosing instead to stay silent for ~14 hours.
No weapon (pistol/knife) was ever recovered; only one spent cartridge was seized. Post-mortem revealed a single gunshot, contradicting claims of two shots.
The High Court mis-appreciated evidence and ignored binding precedents governing appellate interference with an order of acquittal.

Accordingly, the appellants were acquitted; any requirement to surrender stood discharged.

3. Analysis

3.1 Precedents Cited and Their Role

The Court built its ratio around a line of earlier authorities examining “unnatural conduct” of eyewitnesses:

Alil Mollah v. State of W.B., (1996) 5 SCC 369 – solitary eyewitness disbelieved because he neither helped his employer nor spoke of the murder until the next day.
Gopal Singh v. State of M.P., (2010) 6 SCC 407 – witness vanished for hours after incident; conviction reversed.
Shivasharanappa v. State of Karnataka, (2013) 5 SCC 705 – daughter’s silence for two days held inconsistent with natural human behaviour.
Lahu Kamlakar Patil v. State of Maharashtra, (2013) 6 SCC 417 – witness fled to another city without telling anyone; testimony rejected.
Amar Singh v. State (NCT of Delhi), (2020) 19 SCC 165 – two brothers’ non-intervention and failure to seek medical help deemed unnatural.
NARENDRASINH KESHUBHAI ZALA v. STATE OF GUJARAT, (2023) 18 SCC 783 – adult witness went home and slept instead of seeking help; conviction overturned.

These cases crystallise a principle that the post-incident conduct of a witness can undercut the reliability of otherwise direct testimony. The present judgment consolidates them into what may now be dubbed the Unnatural-Conduct Test.

3.2 The Court’s Legal Reasoning

Credibility hinges on natural human behaviour.
The bench held that a witness’s account should reflect “a real image in a mirror”. Conduct such as fleeing without reporting, keeping silent for long intervals, or failing to procure medical aid is antithetical to expected human reactions, especially where the deceased is a close relative.
Lack of forensic corroboration compounds doubt.
Absence of weapon recovery, ballistic matching, or scientific evidence prevented the prosecution from buttressing the shaky ocular version.
Appellate interference with acquittal demands compelling reasons.
Re-iterating Chandrappa v. State of Karnataka (2007) 4 SCC 415, the Court emphasised that unless the trial court’s view is perverse, the presumption of innocence continues after acquittal. The High Court’s reversal, resting solely on the same ocular evidence discarded by the trial court, lacked such compelling justification.

3.3 Potential Impact

Eyewitness scrutiny will intensify. Prosecutors must now address “conduct consistency” during examination-in-chief, anticipating meticulous cross-examination on post-incident behaviour.
Greater reliance on forensic evidence. Where eyewitnesses are relatives, courts will expect objective corroboration – ballistic reports, CCTV, digital footprints, call data – to allay suspicion of tutoring or bias.
Restraint on appellate reversal of acquittals. High Courts must explicitly demonstrate perversity or grave legal error; mere difference of opinion will not suffice.
Training for investigating officers. IOs will need to secure prompt, recorded statements, and explain any delay, lest the “unnatural conduct” tag weaken their case.

4. Complex Concepts Simplified

Unnatural Conduct Test: A judicial yardstick asking whether a witness’s behaviour during and immediately after the crime aligns with how an ordinary person would react in similar circumstances.
Fardbeyan: A statement recorded at the earliest point (often at the scene/hospital) which becomes the basis of the First Information Report (FIR).
Section 302/34 IPC: Murder committed with common intention – each participant is liable as if he committed the act alone.
Section 27 Arms Act: Punishes use of prohibited weapons; conviction usually requires proof of possession and ballistic matching.
Spent cartridge / ballistic report: Forensic linkage between the fired cartridge and a specific firearm; absence weakens firearm-use allegations.
Reversal of acquittal: An appellate setting aside of a not-guilty verdict; permissible only when the trial court’s view is “clearly unreasonable or perverse”.

5. Conclusion

Nimai Ghosh is not just another reversal; it cements a doctrinal focus on behavioural plausibility and fortifies the threshold for disturbing acquittals. The Supreme Court distilled decades of case-law into a concrete, workable test: when eyewitnesses act in ways no ordinary person would, their testimony – however direct – cannot form the sole basis for conviction unless robustly corroborated. Investigators, prosecutors, and appellate judges must now internalise this standard: credibility is measured not only by what a witness says but by what the witness did, or failed to do, in the crucial moments following the crime. The judgment is thus poised to influence trial strategies, police procedures, and appellate review for years to come.