In the landmark Kattavellai @ Devakar v. State of Tamil Nadu case (2025), the Supreme Court of India has established crucial guidelines to govern the collection, preservation, and handling of DNA evidence in criminal investigations. This judgment aims to ensure the scientific integrity and legal admissibility of forensic evidence, preventing miscarriages of justice.

Key Supreme Court Guidelines on DNA Evidence Handling

To standardize the procedure and maintain the sanctity of DNA evidence, the Court mandated the following:

1. Proper Documentation at Collection: A detailed document must be prepared at the time of sample collection, recording the FIR number, details of the investigating officer, and signatures of the medical professional and independent witnesses. Crucially, samples must be sealed and cannot be opened or resealed without explicit authorization from the trial court.

2. Timely Transportation: The investigating officer is now required to transport the collected DNA samples to the designated Forensic Science Laboratory (FSL) within a strict timeline of 48 hours to prevent degradation.

3. Strict Maintenance of Chain of Custody: A Chain of Custody Register must be meticulously maintained, tracking the sample from the moment of collection until the final closure of the case. This register is a mandatory part of the trial court record, ensuring a verifiable and unbroken trail for the evidence.

Challenges in DNA Evidence Management

The Supreme Court’s guidelines address several persistent issues that can compromise the reliability of DNA evidence:

• Collection and Preservation: DNA is highly susceptible to contamination from other biological material and degradation due to environmental factors like heat and moisture.

• Analysis and Reliability: The process is vulnerable to human error, cognitive bias during analysis, and a lack of standardized protocols across different laboratories, which can affect the accuracy of the results.

• Privacy and Ethical Issues: The creation and maintenance of DNA databases raise significant privacy concerns, including the potential for function creep (using data for purposes other than intended), state surveillance, and genetic discrimination.

• Interpretation: There is a risk of overreliance on DNA evidence by courts. Interpreting complex mixtures from multiple individuals or trace DNA can be challenging and may lead to wrongful convictions if not corroborated with other evidence.

Judicial Evolution of DNA Evidence in India

The legal standing of DNA evidence in India has evolved through several key judgments and legislative changes.

• • The technology was first used in the Kunhiraman v. Manoj case (1991) to resolve a civil paternity dispute.

  • In Sharda v. Dharmpal (2003), the Supreme Court held that compelling a person to provide a DNA sample does not violate the Right to Life and Personal Liberty (Article 21) or the Right against Self-Incrimination (Article 20(3)).

  • The Bharatiya Nagarik Surakhsha Sanhita, 2023 (BNSS), under Section 51, now provides statutory backing for the medical examination of an arrested person, including DNA profiling.

  • However, courts have consistently emphasized procedural integrity. In Rahul v. State of Delhi (2022), DNA evidence was rejected because the sample remained in police custody for an extended period, raising concerns about tampering.

  • The latest Devakar case (2025) classifies DNA evidence as “opinion evidence” under Section 39 of the Bharatiya Sakshya Adhiniyam, 2023 (BSA). This clarifies that DNA evidence is not conclusive proof on its own; its evidentiary value must be assessed in the context of each case and requires both scientific and legal validation.

Conclusion

The Supreme Court’s guidelines in the Kattavellai @ Devakar case are a critical step towards strengthening the criminal justice system. By mandating a uniform, scientifically sound, and transparent procedure for handling DNA evidence, the Court aims to bolster its reliability while acknowledging its limitations. This ensures that while modern technology is used to aid justice, it is subjected to rigorous legal standards to protect the rights of individuals.

UPSC PYQs

Q. Consider the following statements: DNA Barcoding can be a tool to:(2022)

1.assess the age of a plant or animal.

2.distinguish among species that look alike.

3.identify undesirable animal or plant materials in processed foods.

Which of the statements given above is/are correct?

(a) 1 only

(b) 3 only

(c) 1 and 2

(d) 2 and 3

Ans: (b)

Q. With reference to the recent developments in science, which one of the following statements is not correct? (2019)

(a) Functional chromosomes can be created by joining segments of DNA taken from cells of different species.

(b) Pieces of artificial functional DNA can be created in laboratories.

(c) A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory.

(d) Cells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes.

Ans: (a)