Context:

The Supreme Court of India recently, in a landmark judgment in Kattavellai @ Devakar v. State of Tamil Nadu, has issued uniform national guidelines to regulate the collection, handling, and presentation of DNA evidence in criminal cases.

Significance of the Guidelines:

In the Devakar case, which involved charges of rape, murder, and robbery, the Court found unexplained delays in sending vaginal swab samples to the Forensic Science Laboratory (FSL) and a missing chain of custody, raising serious doubts about the reliability of the DNA evidence.

·        Although some states had issued internal guidelines, the absence of uniform national procedures prompted the Supreme Court to intervene.

About DNA:

DNA (Deoxyribonucleic Acid) is the genetic blueprint for all living organisms, responsible for heredity, cell function, and protein synthesis.

·        DNA carries instructions passed from parents to offspring and defines traits such as eye color, height, and disease susceptibility.

·        DNA is made of two long chains called polynucleotides, each composed of nucleotides containing a sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), or guanine (G).

·        These bases pair specifically (A with T, C with G) through hydrogen bonds.

About Four Key Guidelines:

·        Proper Documentation at Collection: Once DNA samples are collected, they must be appropriately labeled with the FIR number, date, relevant legal sections, and details of the investigating officer and medical examiner. Signatures from all involved, including independent witnesses, must be recorded to establish accountability.

·        Timely Transfer to FSL: The investigating officer must ensure the DNA sample is delivered to the FSL within 48 hours of collection. Any delay must be recorded with valid reasons, and steps must be taken to preserve the sample during the interim.

·        Secure Storage Pending Trial: While awaiting trial or appeal, DNA samples must not be opened, altered, or resealed without the express authorization of the trial court. This ensures the evidence remains untainted.

·        Maintaining the Chain of Custody Register: A detailed Chain of Custody Register must be maintained from the point of collection until the conclusion of the case (conviction/acquittal). This register becomes part of the trial court record. The investigating officer is held accountable for any procedural lapses.

Supreme Court earlier decisions on DNA:

• The Court clarified that DNA evidence is a form of opinion evidence under Section 45 of the Indian Evidence Act (Section 39 of the Bharatiya Sakshya Adhiniyam, 2023). This means it is not conclusive and must be weighed along with other evidence in the case.
• A match between DNA from a crime scene and a suspect indicates a common biological origin, but does not by itself establish guilt.

Major rulings:

• Anil v. State of Maharashtra (2014): DNA is valid and reliable, but only when lab quality control is ensured.
• Manoj v. State of Madhya Pradesh (2022): DNA from an open area was rejected due to possible contamination.
• Rahul v. State of Delhi (2022): DNA stored in police custody for two months was deemed unreliable due to potential tampering.

Conclusion:

The Supreme Court’s guidelines mark a vital step toward reforming forensic practices in India’s justice system. While DNA evidence can greatly aid investigations, it requires strict, uniform protocols to be legally reliable. By enforcing documentation, timely processing, and chain-of-custody standards, the Court has ensured greater transparency and accountability. These rules now provide a binding framework for all states, reinforcing that justice depends on both scientific rigor and procedural fairness.