THE SILENT SPECTATOR OF THE CRIME: ROLE OF FORENCSIC SCIENCE IN CRIMINAL CONVICTION

INTRODUCTON

“Can a case still be solved if there was no reliable evidence available?” Yes perhaps. Techniques like fingerprints and DNA to toxicology, ballistics, digital evidence, forensic science can connect a suspect with a crime scene, identify victim and establish the truth before the court. Forensic science plays a crucial role in the modern criminal justice system. Basic organic substances such as cell, hair or nail to complex chemical can sometime be enough to find a criminal or prove the innocence of a falsely accused. Applying scientific methods for investigation or prosecution helps courts to have jurisdiction over the case. It restrains the court to solely rely on eyewitness, testimony or simple confessions.

Forensic science is now considered significant with advancement in technology but forensic evidences are only conclusive if the evidence is properly collected, preserved, examined, interpreted, and presented before the court. Forensic science is not merely to obtain convictions but to assist the court in discovering the truth.

Indian courts have repeatedly brought attention that scientific evidence must be evaluated in accordance with its reliability, relevance, and connection with the facts of the particular case. Expert opinion can assist the court, but the ultimate determination of guilt remains a judicial function.

This article state that the evolving biology and information sector have greatly affected the quality of jurisdiction. The article proceeds as follows. Section II consist of criminal trial requiring key forensics. Section III talks about the role in criminal investigation.  Section IV emphasizes on statutory framework and permeability. Section V states key landmark cases.  Section VI structural changes and limitation. The article then end with a conclusion on the use of forensic science.

CRIMINAL TRIAL REQUIRING KEY FORENSIC MODALITIES

DNA profiling

DNA or deoxyribonucleic acid contains genetic information present in almost all nucleated cells of the human body. Biological material such as blood, saliva, semen or certain tissue samples can therefore provide a potential source of DNA. DNA profiling examines selected regions of the genome and generates a genetic profile. The National Research Council’s 2009 report distinguished nuclear DNA analysis from several other forensic techniques and observed that  it has a substantially stronger scientific foundation for establishing a connection between biological evidence and an individual source than many other forensic disciplines. A DNA match tells an association between a person and biological material, but the legal significance of that association depends upon the circumstances of the case. Questions of transfer, contamination, persistence, secondary transfer and the manner in which the biological material reached the scene are very relevant.

Indian courts have recognised the evidentiary importance of DNA while also emphasizing that it constitutes expert evidence requiring appropriate legal proof. In Rahul v. State of Delhi, the Supreme Court considered problems relating to the collection and proof of DNA evidence.

Fingerprint analysis

Fingerprints arise from friction-ridge patterns on the fingers and palms. Their patterns contain characteristics that can be compared between a questioned impression and a known print from the crime scene. Fingerprint evidence can assist in linking a person to an object or location. Under Section 39 of the BSA, opinions concerning the identity of finger impressions are expressly recognised as relevant expert opinions. Factors such as the quality of the latent print, distortion, substrate, examiner methodology, documentation and possibility of error can affect interpretation. Court should rely on experts.

Digital forensic

Computers, mobile phones, cloud accounts, CCTV systems, social-media records and other electronic systems may contain information relevant to a crime. Digital forensic examination can recover, preserve and interpret electronic information. It may establish communications, file activity, photographs, metadata, internet activity or other information relevant to a criminal allegation. Digital evidence also presents special challenges. Data may be deleted, altered, encrypted or remotely accessed. Investigators must therefore preserve original evidence and document acquisition and handling procedures. Digital forensic conclusions should be reproducible and based upon properly authenticated material.

Indian law specifically recognises expert involvement in electronic evidence. Section 39(2) of the BSA provides that where a court has to form an opinion concerning information transmitted or stored in a computer resource or other electronic or digital form, the opinion of an Examiner of Electronic Evidence referred to in Section 79A of the Information Technology Act, 2000 is a relevant fact.

Toxicology

It examines biological specimens for drugs, alcohol, poisons and other toxic substances. It may become relevant in suspected poisoning, drug-related deaths, impaired driving and other offences.

The scientific identification and quantification of a substance can help establish whether a particular compound was present in a person’s body. Interpretation requires care because the mere presence of a substance does not always establish its effect, timing or role in death. Toxicological findings must therefore be interpreted together with medical history, autopsy findings, dosage information and other evidence.

This illustrates an important principle: forensic science rarely operates in isolation. The strongest criminal cases frequently arise when independent forms of evidence converge.

ROLE IN CRIMINAL INVESTICATION

Forensic sciences role starts from the crime scene itself. The evidence must be carefully identified, documented, collected and preserved. Any error can contaminate the evidence and thus effect the judgment.

Forensic technique determines:

1. Presence of the suspects at the crime scene;
2. How offence was committed;
3. Weapons or instruments used;
4. Time and situation in which the victim died;
5. Whether digital evidence has been altered or manipulated.

Thus, forensic science can explain the apparently unexplained circumstances.

STATUTORY FRAMEWORK AND PERMIABILITY

Forensic evidences are derived from the statutory authority primarily throughout key provision across procedural, substantive and evidentiary codes.

Expert Testimony: Section 45 of the Indian Evidence Act, 1872 (now reflected in Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 -BSA) provides expert opinion acceptable when the court requires specialized knowledge in fields like science, art, handwriting, or finger impressions for fair judgment.

Constitutional Safeguards: Article 20(3) of the Constitution of India guarantees protection against self-incrimination. The landmark judgment in State of Bombay v. Kathi Kalu Oghad (1961) stated that constraining an accused to give physical samples (fingerprints, handwriting, blood) does not violate Article 20(3), as these are bodily attributes, not “testimonial compulsion”.

Compulsory Forensic Mandates: Under recent legislative updates like the Bharatiya Nagarik Suraksha Sanhita, 2023 (BNSS) (which replaced the old code of criminal procedure), forensic investigations have been made mandatory for offences punishable by 7 years or more.

Judicial Paradigm: Key Landmark Cases

1. Mukesh & Anr. v. State (NCT of Delhi) (2017) – The Nirbhaya Case

Issue: Admissibility and weight of bite-mark analysis and DNA profiling in brutal sexual assault case in Delhi.

Observation: The Supreme Court dependent on forensic evidence to support the death penalty for the accused. DNA extracted from samples collected from the victim matched the accused persons almost perfectly. Moreover, 3D dental models and bite-mark analysis provided physical linkage. The Court affirmed that scientific evidence, when collected precisely, creates an unbroken chain of custody that withstands the standard of reasonable doubt.

2. Selvi v. State of Karnataka (2010) -Limits of Involuntary Forensic Testing

Issue: Constitutional validity of involuntarily subjecting an accused to Narco-analysis, Polygraph tests, and Brain Electrical Activation Profiling (BEAP).

Observation: The Supreme Court marked a clear boundary between physical evidence (DNA, fingerprints) and compulsory neurological or psychological testing. The Court ruled that forced involuntary administration of narco-analysis tests violates the fundamental right to privacy under Article 21 and the privilege against self-incrimination under Article 20(3). Any physical information or material recovered consequent to voluntary statements can be admissible under Section 27 of the Evidence Act.

3. Santosh Kumar Singh v. State (2010):The Priyadarshini Mattoo Case

Issue: Reversal of acquittal based on reliable DNA evidence over weak circumstantial testimony.

Observation: The trial court had initially acquitted the accused due to doubts regarding chain of custody. On appeal, the High Court and subsequently the Supreme Court held that when procedural protocols are maintained, DNA evidence acts as an indisputable signature of presence and involvement, sufficient to secure a conviction in circumstantial cases.

Structural Challenges

Despite the efficacy of forensic science, it is not error free. Several operations are still hindered during its optimal execution in trials:

1. Contamination & Chain of Custody: Errors during scene of crime preservation, improper sampling, or broken chains of custody can hinder biological evidence unreliable or legally inadmissible.
2. Lack of Standardized Certification: Varying protocols across regional Forensic Science Laboratories (FSLs) often result in severe backlogs and delays in submitting expert reports hindering the courts judgment or time for manipulation of the evidences.
3. Judicial Evaluation vs. Reliance: Courts must avoid treating forensic opinions as automatic substitutes for judicial reasoning. An expert opinion is advisory under law; it requires conformation alongside the facts of the case.

LIMITATION

Though we have came a long way in science still there are ways that put forensic science uses in a questionable ground.

A usual case of misapplied forensic science lies in the serology. It involves reading and evidences about a phenomenon known as masking that Humans have different blood types, which are inherited from our parents and are determined by the presence or absence of different antigens. Type A, Type B, Type AB, And Type O are the four major groups in the ABO blood group system and occur at different frequencies in different ethnic populations. The ABO blood group markers can be detected in blood, but approximately 80% of the population also secretes blood group substances in their other bodily fluids (e.g., Saliva, semen, vaginal fluid). If a sample of bodily fluid contains a mixture of a relatively large amount of the victim’s biological material and a relatively small Amount of the perpetrator’s biological material (as is often the case in instances of rape), the victim’s contribution can overwhelm the perpetrator’s, rendering The perpetrator’s blood type unidentifiable or masked. So, while ABO Blood grouping is a scientifically valid and reliable way but can also be misleading in specific circumstances , suggesting that someone is a possible contributor without clarifying that, in instances of potential masking, literally anyone could be the donor is misleading and is a misapplication of forensic science.

 CONCLUSION          

 Judges should consider the qualifications of the expert, methodology employed, condition and source of the sample, possibility of contamination, reliability of the testing procedure, and consistency of the forensic findings with other evidence on record. The court should also have a watch over the procedure so that chances of forceful contamination can be lowered down. Scientific evidence should neither be rejected merely because it is technical nor accepted unquestioningly because it is presented as scientific. There is a need of proper Judicial Scrutiny Courts. Court must adopt a balanced approach in using forensic evidences.

The principle of presumption of innocence also remains fundamental. Forensic science should strengthen the search for truth while ensuring that an accused person is not convicted merely because scientific evidences appears without any other reliable proof of its reliability, its scientific techniques that help courts ascertain the truth and uphold justice, forensic science has become an essential part of contemporary criminal investigations.

Tough these techniques have potential, these techniques are significant concerns about their scientific validity, legal admissibility, and compatibility with constitutional rights, including the right to privacy and the right against self-incrimination. This article supports the idea that only when forensic science is applied with methodical examination that strikes a balance between probative value and legal and ethical safeguards can it significantly improve the fairness and accuracy of judicial decision-making.

The study attempts to create a logical framework for incorporating science into criminal justice without sacrificing fundamental rights by objectively assessing the evidentiary value of important forensic techniques.

CITING

1. Bharatiya Sakshya Adhiniyam, 2023, Act No. 47 of 2023, India Code, particularly Sections 3, 39–45.
2. Bharatiya Sakshya Adhiniyam, 2023, Section 39 (Opinions of experts) and Section 40 (Facts bearing upon opinions of experts).
3. Bharatiya Nagarik Suraksha Sanhita, 2023, Section 329 (Reports of certain Government scientific experts).
4. Manoj & Ors. v. State of Madhya Pradesh, (2023) 2 SCC 353, as discussed by the Supreme Court concerning DNA evidence, contamination and proper preservation.
5. Pattu Rajan v. State of Tamil Nadu, (2019) 4 SCC 771, concerning the probative value of DNA evidence.
6. Supreme Court of India, decisions concerning the evidentiary value of expert and DNA evidence.
7. Mukesh & Anr. v. State (NCT of Delhi) & Ors.
   1. Reporter Citation: (2017) 6 SCC 1
   2. Parallel Citation: AIR 2017 SC 2161
8. Selvi & Ors. v. State of Karnataka
   1. Reporter Citation: (2010) 7 SCC 263
   2. Parallel Citation: AIR 2010 SC 1974
9. Santosh Kumar Singh v. State through CBI
   1. Reporter Citation: (2010) 12 SCC 588
   2. Parallel Citation: 2010 Cri LJ 4964