1. Introduction

Failure to preserve forensic evidence after an incident is a serious issue in criminal investigation, civil litigation, and the administration of justice. Forensic evidence plays a crucial role in establishing the facts and circumstances surrounding an incident, identifying the persons responsible, determining the sequence of events, and corroborating or disproving witness statements.

Forensic evidence may include:

DNA samples, bloodstains, hair, saliva and other biological materials.

Fingerprints, footprints and palm prints.

CCTV footage and video recordings.

Mobile phones, computers, hard disks and other electronic devices.

Call Detail Records (CDRs), location data and digital communications.

Weapons, clothing, fibres, soil, glass fragments and other physical objects.

Medical examination reports, post-mortem reports and toxicological samples.

Photographs, scene-of-crime records and forensic laboratory reports.

When an investigating agency, responsible authority, institution or other person fails to secure and preserve such evidence immediately after an incident, the evidence may be destroyed, contaminated, altered, overwritten, misplaced or rendered scientifically unreliable.

This failure can seriously prejudice the investigation and the rights of the parties involved.

The central legal principle is that the duty to investigate does not end with collecting evidence. It also includes taking reasonable steps to secure, preserve, document, maintain and produce relevant evidence in a condition that allows its authenticity and reliability to be examined.

2. Meaning of failure to preserve forensic evidence

Failure to preserve forensic evidence means an omission, negligence or deliberate act by a person or authority responsible for safeguarding relevant evidence, resulting in its loss, destruction, contamination, alteration or unavailability.

Such failure may occur at different stages:

Immediately after the incident: Failure to secure the crime scene or prevent unauthorised access.

During evidence collection: Failure to use appropriate collection methods, protective equipment or contamination-prevention procedures.

During transportation: Failure to properly seal, label and transport samples.

During storage: Failure to maintain appropriate temperature, security and environmental conditions.

During forensic examination: Failure to document the examination process or maintain the integrity of samples.

During investigation and trial: Failure to produce relevant forensic material, original electronic records or chain-of-custody documentation.

It is important to distinguish between accidental loss, negligent preservation and intentional destruction of evidence. Their legal consequences may differ depending on the facts, applicable statutory provisions and the degree of culpability.

3. Legal framework governing preservation of forensic evidence in India

A. Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS)

The BNSS, which came into force on 1 July 2024, provides the procedural framework for criminal investigation.

Section 176(3) BNSS – Forensic investigation of offences

This provision requires forensic experts to visit the crime scene, collect forensic evidence and videograph the process in the prescribed category of offences, namely offences punishable with imprisonment of seven years or more, subject to the statutory implementation arrangements.

This provision reflects the importance of scientific investigation and proper documentation of crime scenes.

Failure to comply with applicable forensic-investigation requirements may raise questions regarding the fairness, completeness and reliability of the investigation.

B. Bharatiya Sakshya Adhiniyam, 2023 (BSA)

The Bharatiya Sakshya Adhiniyam, 2023, governs the admissibility and proof of evidence.

Important provisions include:

Section 39: Opinions of experts, including forensic experts, are relevant when the Court has to form an opinion on a point of science or other specialised knowledge.

Section 61: Electronic or digital records are not to be denied admissibility merely because they are electronic or digital.

Section 62: Special provisions relating to proof of electronic records.

Section 63: Admissibility of electronic records, subject to the statutory requirements.

The practical importance of these provisions is that the electronic evidence must be capable of being properly authenticated and proved. Merely producing a printout or an electronic file does not automatically establish its authenticity.

C. Indian Penal Code and Bharatiya Nyaya Sanhita, 2023

For incidents occurring under the present criminal law framework, the relevant provisions of the Bharatiya Nyaya Sanhita, 2023 (BNS), must be considered.

Section 238 BNS – Causing disappearance of evidence of offence, or giving false information to screen offender

This provision addresses conduct involving the disappearance of evidence or the giving of false information with the intention of screening an offender from legal punishment.

Where forensic evidence is intentionally destroyed or concealed to protect an accused person, the provision may become relevant, provided its statutory ingredients are established.

For earlier offences, the corresponding provision under the Indian Penal Code was Section 201 IPC.

D. Constitutional protection under Article 21

Article 21 of the Constitution guarantees the right to life and personal liberty.

The right to a fair investigation and fair trial forms an important component of Article 21.

An investigation that ignores material forensic evidence, permits avoidable destruction of evidence or selectively collects evidence may raise constitutional concerns, particularly where such conduct affects the fairness of criminal proceedings.

However, every procedural lapse does not automatically amount to a violation of Article 21. The nature of the failure and its effect on the investigation or trial must be examined.

4. Meaning and importance of chain of custody

One of the most important aspects of forensic evidence preservation is the chain of custody.

Chain of custody refers to the chronological documentation of the collection, possession, transfer, storage, examination and production of forensic evidence.

It establishes:

Who collected the evidence.

When and where it was collected.

How it was collected.

Whether it was properly sealed and labelled.

Who handled or transferred it.

Where it was stored.

Whether the seal remained intact.

When it was sent to the Forensic Science Laboratory (FSL).

Whether the evidence received by the laboratory was the same evidence originally collected.

Why is chain of custody important?

Suppose blood samples are collected from a crime scene. The investigating officer fails to seal them properly, and the samples remain exposed for several hours before being sent to the laboratory.

This creates several possibilities:

The sample may become contaminated.

The biological material may deteriorate.

The sample may be mixed with another sample.

Its original source may become uncertain.

The defence may challenge the authenticity and reliability of the forensic report.

Consequently, even where a forensic laboratory produces a scientific report, the Court may have to examine whether the material tested was properly collected, preserved and connected with the incident.

Important: A defect in the chain of custody does not automatically make forensic evidence inadmissible. Its effect depends upon the seriousness of the defect, the available corroboration and whether the identity and integrity of the material can still be established.

5. Important judicial pronouncements and case laws

The Supreme Court of India has repeatedly emphasised the importance of reliable investigation, scientific evidence, preservation of material evidence and the consequences of withholding relevant evidence.

Case 1. Tomaso Bruno & Anr. v. State of Uttar Pradesh (2015)

SUPREME COURT OF INDIA · (2015) 7 SCC 178 · 20 JANUARY 2015

Important judgment

Facts of the case:

The case concerned the death of an Italian national in a hotel room in Varanasi. The prosecution alleged that the deceased had been strangulated by the accused persons.

The accused persons claimed that they had gone outside the hotel and returned later, finding the deceased in a serious condition.

The hotel had CCTV cameras installed at important locations. However, the investigating agency failed to collect and produce the relevant CCTV footage. The investigating officer also failed to collect important call detail records and SIM-related information.

Issue before the Supreme Court:

Whether the failure to collect and produce CCTV footage and other relevant electronic evidence could be treated as a mere defect in investigation or as withholding of the best available evidence.

Judgment and legal principles:

The Supreme Court held that non-production of CCTV footage and failure to collect relevant call records could not be dismissed as ordinary defects in investigation.

The Court observed that CCTV footage constituted important evidence and that the prosecution should have produced the best available evidence.

The Court discussed Section 114 Illustration (g) of the Indian Evidence Act, 1872, under which an adverse inference may be drawn where a party withholds evidence that could have been produced.

The Court ultimately found that the circumstances did not establish a complete chain pointing towards the guilt of the accused and set aside their convictions.

Legal significance:

This judgment establishes that:

Investigating agencies should collect relevant electronic evidence.

CCTV footage should not be ignored merely because other forms of evidence are available.

Withholding important evidence may justify an adverse inference.

Failure to collect material evidence may create reasonable doubt in a criminal case.

The Court must examine whether the missing evidence could have materially affected the outcome.

The judgment is particularly important in cases involving the destruction, non-collection or non-production of CCTV footage and other digital evidence.

Case 2. State of Karnataka v. K. Yarappa Reddy (1999)

SUPREME COURT OF INDIA · (1999) 8 SCC 715

Facts and legal issue:

The case dealt with the effect of defects and irregularities in criminal investigation and the responsibility of the Court to evaluate the evidence independently.

Judgment and legal principles:

The Supreme Court explained that defective investigation does not necessarily result in the acquittal of the accused.

The Court must examine the evidence independently and determine whether the prosecution has established its case.

The Court's responsibility is to ensure that the truth is discovered and justice is not defeated merely because the investigating officer has committed an error.

Relevance to forensic evidence preservation:

This principle is relevant where:

The crime scene was not properly secured.

Certain forensic samples were not collected.

The investigating officer failed to maintain proper records.

There were irregularities in the preservation of physical evidence.

However, the Court must assess whether such failures materially affect the prosecution case.

Legal principle: A defective investigation is not automatically fatal, but the Court cannot ignore defects that undermine the reliability of material evidence.

Case 3. H.N. Rishbud and Inder Singh v. State of Delhi (1955)

SUPREME COURT OF INDIA · AIR 1955 SC 196

Facts and legal issue:

The Supreme Court examined the legal consequences of irregularities in criminal investigation and the effect of procedural defects on subsequent proceedings.

Judgment and legal principles:

The Court explained the different stages of criminal investigation, including:

Proceeding to the place of occurrence.

Ascertainment of the facts and circumstances.

Discovery and arrest of suspected offenders.

Collection of evidence relating to the commission of the offence.

Formation of an opinion as to whether there is sufficient evidence to prosecute.

The Court recognised that irregularities in investigation do not automatically invalidate the entire criminal proceeding.

Relevance to preservation of forensic evidence:

The collection of evidence is an essential part of investigation. Failure to properly collect and preserve material evidence may compromise the investigation.

The decision provides the foundational procedural understanding of the investigating officer's responsibilities.

Case 4. Pooja Pal v. Union of India (2016)

SUPREME COURT OF INDIA · (2016) 3 SCC 135

Facts of the case:

The matter concerned the fairness and credibility of a criminal investigation and the circumstances in which an independent investigation could be required.

Judgment and legal principles:

The Supreme Court emphasised that a fair investigation is an essential component of the constitutional guarantee under Article 21.

The Court recognised that the right to a fair investigation is not merely a procedural formality. It is an important aspect of the administration of criminal justice.

Relevance to forensic evidence preservation:

If an investigating agency deliberately ignores important forensic evidence, fails to preserve relevant material or conducts an incomplete investigation, questions may arise concerning the fairness and credibility of the investigation.

An appropriate constitutional remedy may be available where the facts demonstrate serious investigative failure and the circumstances justify judicial intervention.

Case 5. Sukhram v. State of Maharashtra (2007)

SUPREME COURT OF INDIA · (2007) 7 SCC 502

Legal issue:

The case concerned the ingredients of the offence of causing disappearance of evidence under Section 201 of the Indian Penal Code.

Judgment and legal principles:

The Supreme Court explained that for establishing an offence under Section 201 IPC, the prosecution must establish:

An offence has been committed.

The accused knew or had reason to believe that such an offence had been committed.

The accused caused evidence of the commission of that offence to disappear or gave false information.

The accused acted with the intention of screening the offender from legal punishment.

Relevance to forensic evidence preservation:

This judgment is particularly relevant where evidence is not merely lost accidentally but is deliberately destroyed, concealed or removed to protect an offender.

For example:

Deliberately destroying blood samples.

Removing a weapon from the crime scene.

Destroying CCTV recordings.

Concealing biological samples.

Altering or destroying records to prevent identification of the offender.

However, mere negligence or an unexplained failure to preserve evidence does not automatically establish an offence under Section 201 IPC or its present equivalent, Section 238 BNS. The required mental element and other statutory ingredients must be proved.

Case 6. Ajay Kumar Ghoshal v. State of Bihar (2017)

SUPREME COURT OF INDIA · (2017) 12 SCC 699

Legal issue:

The Supreme Court considered the circumstances in which an appellate Court may order a retrial because of serious defects in the original proceedings.

Judgment and legal principles:

The Court explained that retrial is an exceptional remedy and should not be ordered merely because there are irregularities or deficiencies in investigation.

There must be a serious illegality, irregularity or failure of justice that justifies such an exceptional direction.

Relevance to forensic evidence:

Where material forensic evidence has been destroyed or improperly preserved, the Court must examine whether the failure has caused substantial prejudice or miscarriage of justice.

The mere existence of an investigative lapse is not sufficient, by itself, to justify a retrial.

Case 7. Supreme Court judgment on forensic chain of custody and investigation (28 January 2025)

SUPREME COURT OF INDIA · CRIMINAL APPEALS NOS. 850–851 OF 2019 · JUDGMENT DATED 28 JANUARY 2025

Facts and legal issue:

The Supreme Court examined serious deficiencies in an investigation involving the prosecution's reliance on circumstances such as motive, last-seen evidence and recovery of material objects.

One of the important deficiencies was the investigating officer's failure to collect evidence regarding the safe custody of recovered articles and material objects until they reached the Forensic Science Laboratory.

Judgment and legal principles:

The Supreme Court criticised the failure to establish how recovered articles were safely kept before being delivered to the forensic laboratory.

The Court considered this omission an important investigative deficiency that contributed significantly to the failure of the prosecution case.

The Court also criticised the inadequate handling of the prosecution evidence during trial.

Legal significance:

This judgment is particularly important because it demonstrates that the mere recovery of an object is not sufficient.

The investigating agency must establish the safe custody and continuity of the material object until it reaches the forensic laboratory.

A failure to demonstrate this continuity can seriously weaken the evidentiary value of the forensic examination.

Central principle: Preservation of evidence is as important as its collection. A forensic report cannot cure every defect in the handling and custody of the material examined.

Case 8. Judgment concerning integrity of crime scene and forensic collection (20 May 2022)

SUPREME COURT OF INDIA · JUDGMENT DATED 20 MAY 2022

Legal issue:

The Supreme Court considered issues relating to the integrity of a crime scene, fingerprint collection, elimination prints and the possibility of contamination of physical evidence.

Judgment and legal principles:

The Court examined whether the crime scene had been secured and whether unauthorised persons could have contaminated the evidence.

It discussed the importance of obtaining elimination fingerprints from individuals who may have touched surfaces or objects at the crime scene.

The Court also clarified that non-compliance with certain procedural requirements does not invariably render evidence inadmissible. The Court must examine the circumstances and the actual effect of the irregularity.

Relevance:

This decision demonstrates the importance of:

Securing the crime scene.

Preventing unauthorised access.

Documenting the persons who enter the scene.

Obtaining elimination fingerprints where appropriate.

Establishing the reliability of collected physical evidence.

It also demonstrates that the Court evaluates the actual possibility of contamination rather than treating every procedural omission as automatically fatal.

6. Legal consequences of failure to preserve forensic evidence

Failure to preserve forensic evidence may result in several legal consequences.

A. Adverse inference against the investigating agency or party

Under Section 119 of the Bharatiya Sakshya Adhiniyam, 2023, the Court may presume the existence of certain facts, having regard to the common course of natural events and human conduct.

Illustration (g) concerns withholding evidence that could be produced but is not produced.

Where relevant evidence is deliberately withheld or its non-production remains unexplained, the Court may draw an adverse inference.

For example:

CCTV footage was available but was not seized.

A mobile phone was recovered but not examined.

Relevant biological samples were collected but not sent for forensic examination.

An institution had access to incident recordings but failed to preserve them despite being aware of their importance.

The principle in Tomaso Bruno v. State of Uttar Pradesh is particularly relevant here.

However, adverse inference is discretionary, not automatic. The Court considers whether the evidence existed, whether it was accessible to the concerned party, whether it was material and whether a satisfactory explanation for its absence exists.

B. Benefit of doubt to the accused

Where the prosecution relies upon circumstantial evidence, every important circumstance must be established through reliable evidence.

If forensic evidence is lost, contaminated or improperly preserved, the prosecution may be unable to establish the necessary connection between the accused and the crime.

For example, suppose the prosecution alleges that a bloodstained knife was recovered from the accused.

However:

The knife was not properly sealed.

There is no documentation of its custody.

The sample was not properly identified.

The forensic report cannot establish the source of the blood reliably.

In such circumstances, the Court may conclude that the recovery or forensic examination does not reliably establish the prosecution's allegation.

The accused may receive the benefit of reasonable doubt if the remaining evidence is insufficient to prove guilt beyond reasonable doubt.

C. Violation of the right to a fair investigation

Article 21 of the Constitution protects the right to a fair investigation and fair trial.

Where the investigating agency deliberately suppresses material evidence, selectively collects evidence or fails to take essential steps to preserve evidence, the fairness of the investigation may be questioned.

In appropriate cases, the constitutional courts may consider directions for further investigation, an independent investigation or other appropriate relief.

The remedy depends on the seriousness of the defect and the circumstances of the case.

D. Criminal liability for intentional destruction of evidence

Section 238 of the Bharatiya Nyaya Sanhita, 2023, deals with causing disappearance of evidence of an offence or giving false information to screen an offender.

For incidents governed by the earlier IPC, Section 201 IPC is relevant.

The provision may apply where a person intentionally causes evidence to disappear with the requisite knowledge and intention to screen an offender from punishment.

It is important to distinguish:

E. Further investigation or reinvestigation

Where the failure to preserve evidence seriously affects the investigation, the Court may consider appropriate directions for further investigation.

The object is to ensure that the investigation is fair, complete and capable of establishing the relevant facts.

However, further investigation cannot always restore evidence that has already been permanently destroyed.

For instance, CCTV footage that has been automatically overwritten may be impossible to recover. Similarly, biological samples that have deteriorated may no longer yield reliable forensic results.

This is why timely preservation is essential.

7. Different forms of forensic evidence and the consequences of non-preservation

8. Responsibility of the investigating officer after an incident

An investigating officer has an important responsibility to protect and preserve material evidence.

The following steps are generally essential:

1. Securing the scene

The place of occurrence should be secured immediately to prevent unauthorised entry and contamination.

2. Documentation

Photographs, videos, sketches and contemporaneous notes should be prepared to document the original condition of the scene.

3. Identification of forensic evidence

The investigating officer should identify all potentially relevant physical, biological, medical and electronic evidence.

4. Scientific collection

Evidence should be collected by trained personnel using appropriate scientific methods.

5. Labelling and sealing

Every item should be properly labelled, sealed and documented.

6. Maintaining chain of custody

Each transfer of evidence should be recorded, including the identity of the person receiving it.

7. Safe storage

Evidence should be stored under appropriate conditions to prevent deterioration, contamination or tampering.

8. Timely forensic examination

Samples should be sent to the appropriate forensic laboratory without avoidable delay.

9. Preservation of electronic evidence

CCTV recordings, mobile data, computer records and other digital material should be secured before routine deletion or overwriting.

10. Production before the Court

Relevant forensic material and supporting records should be made available for judicial scrutiny, subject to applicable evidentiary and procedural requirements.

9. Failure to preserve electronic and digital forensic evidence

In modern criminal investigations, electronic evidence is frequently more important than conventional physical evidence.

Examples include:

CCTV recordings from public and private premises.

GPS and location records.

WhatsApp messages and emails.

Mobile phone call records.

Internet Protocol (IP) logs.

Computer and server logs.

Audio and video recordings.

The failure to preserve electronic evidence can permanently destroy important information.

Important legal considerations

A. Immediate preservation

Electronic records should be secured before automatic deletion, overwriting or routine system maintenance.

B. Preservation of original records

Where possible, original electronic media should be preserved, and forensic copies should be created using appropriate procedures.

C. Authentication

The source, authenticity and integrity of electronic records must be established in accordance with the Bharatiya Sakshya Adhiniyam, 2023.

D. Section 63 BSA

The statutory requirements concerning electronic records, including the applicable certificate requirements, must be complied with when relying upon electronic records.

E. Digital forensic examination

The forensic examination should be appropriately documented so that the Court can evaluate the methods used and the reliability of the results.

10. Distinction between negligent failure and intentional destruction of forensic evidence

This distinction is extremely important in determining legal liability.

A person should not automatically be prosecuted for destruction of evidence merely because evidence was lost during investigation. The prosecution must establish the necessary ingredients of the relevant offence.

11. Remedies available when forensic evidence is not preserved

Where forensic evidence has not been preserved, an affected party may consider the following legal remedies, depending on the stage of proceedings.

1. Representation to senior police authorities: Request an explanation for the failure and immediate preservation of any remaining evidence.

2. Application before the Magistrate: Seek appropriate directions concerning investigation and preservation of available material, within the Court's statutory powers.

3. Application for further investigation: Request further investigation where material evidence has not been collected or examined.

4. Application for production of documents or records: Seek production of relevant material in accordance with applicable procedural and evidentiary law.

5. Constitutional remedy: In appropriate cases, approach the High Court under Article 226 or the Supreme Court under Article 32, where constitutional requirements for intervention are satisfied.

6. Challenge during trial: Question the investigating officer and forensic witnesses regarding the collection, handling, storage, transfer and examination of evidence.

7. Departmental proceedings: Where misconduct or negligence is established, appropriate departmental action may be considered.

8. Criminal proceedings: Where deliberate destruction or concealment of evidence is established, appropriate criminal provisions may be invoked.

12. Important legal principles emerging from the judgments

The above judicial pronouncements establish the following principles:

1. Preservation of evidence is an essential component of a fair and effective investigation.

2. Investigating agencies should collect all material evidence that may assist in establishing the truth.

3. Scientific evidence must be collected and handled using appropriate procedures.

4. The chain of custody must establish the identity and continuity of forensic material.

5. Failure to preserve CCTV footage and other electronic records may amount to withholding of important evidence.

6. The Court may draw an adverse inference where material evidence is withheld without satisfactory explanation.

7. Negligent investigation does not automatically result in acquittal, but serious defects affecting the reliability of evidence must be considered.

8. Intentional destruction of evidence may attract independent criminal liability.

9. A forensic report does not automatically establish the reliability of the material examined; its collection and custody must also be examined.

10. The right to a fair investigation and fair trial is protected under Article 21 of the Constitution.

13. Conclusion

Failure to preserve forensic evidence after an incident is not merely a technical or administrative deficiency. It can directly affect the investigation, the admissibility and evidentiary weight of material, the rights of the accused and victims, and the overall administration of justice.

The investigating agency has a responsibility to ensure that material evidence is properly identified, collected, sealed, labelled, stored, transported and scientifically examined.

The judgments in Tomaso Bruno v. State of Uttar Pradesh, K. Yarappa Reddy v. State of Karnataka, H.N. Rishbud v. State of Delhi, Pooja Pal v. Union of India and Sukhram v. State of Maharashtra provide important principles concerning fair investigation, defective investigation, withholding of evidence and intentional disappearance of evidence.

The Supreme Court's judgment dated 28 January 2025 further highlights the importance of establishing the safe custody of recovered articles until they reach the Forensic Science Laboratory.

Ultimately, the law recognises that evidence must not only be collected but must also be preserved in a scientifically reliable and legally verifiable manner. If relevant forensic evidence is lost, contaminated, destroyed or deliberately concealed, the resulting deficiency may seriously undermine the credibility of the investigation and may, in appropriate circumstances, lead to adverse judicial consequences or criminal liability.

14. Important case laws at a glance

Note on statutory applicability: The BNSS, BNS and BSA came into force on 1 July 2024. Proceedings and offences arising under the earlier legal framework may continue to be governed by the corresponding provisions of the CrPC, IPC and Indian Evidence Act, subject to the applicable savings provisions. The statutory provisions must therefore be identified according to the relevant dates and circumstances.