The SC issued Guidelines for Cases where DNA Evidence is Involved

The Supreme Court's Guidelines on DNA Evidence: Strengthening Scientific Integrity or Overcorrecting Procedural Gaps?

On September 15, 2025, the Supreme Court, in Kattavellai @ Devakar v. State of Tamil Nadu, issued procedural guidelines to safeguard deoxyribonucleic acid (DNA) evidence in criminal cases. Among its directives: transportation of DNA samples to forensic labs within 48 hours, and the maintenance of an exhaustive Chain of Custody Register tracing the evidence from collection to trial outcomes. The Court's rationale? Severe lapses in sample handling and storage threaten both forensic validity and legal reliability. While these guidelines aim to standardize practices across states, they also amplify tensions between central judicial directives and state-level autonomy, especially since ‘Police’ is deeply embedded in the State List under the Constitution.

The Scientific and Legal Dilemma

DNA evidence occupies an uneasy space in Indian criminal law. Technically compelling, yet judicially categorized as an expert opinion under Section 45 of the Indian Evidence Act, its admissibility hinges on both procedural integrity and circumstantial corroboration. The Court in Devakar rightly flagged contamination risks—beyond poor sample preservation, delays of weeks or months before forensic analysis can undermine evidentiary value. For instance, in Rahul v. State of Delhi (2022), a DNA sample stored in a police Malkhana for two months led to its judicial rejection due to tampering concerns.

The guidelines supplement the existing legal framework by enforcing transparency in collection and chain-of-custody processes. Officials overseeing DNA samples must now log every movement, resampling, and modification. At face value, these measures promise greater scientific rigor in convictions, aligning forensic evidence with admissibility standards set in Anil v. State of Maharashtra (2014), where the Court emphasized procedural quality control. However, the persistent lack of uniformity across investigative agencies suggests that coordination among states—and not judicial diktats alone—will determine their success.

The Case for Strengthened Guidelines

Proponents of these guidelines point to glaring lapses in the forensic pipeline. A 2023 audit revealed that approximately 25% of DNA samples reaching Forensic Science Laboratories (FSL) were found to be partially degraded due to improper handling. Delayed submissions, particularly in smaller states where FSL infrastructure remains insufficient, further complicate matters. Centralized procedures could curb contamination risks, protect biological integrity, and reduce reliance on circumstantial evidence that often skews judicial outcomes.

Moreover, India's crime investigation process suffers from overburdened forensic labs. According to the National Crime Records Bureau, in 2022, over 50,000 cases involving biological evidence clogged labs nationwide, with a manpower deficit of nearly 30% of sanctioned positions. Setting strict transportation and storage timelines may not resolve capacity constraints but provides investigators a roadmap for compliance. International examples, such as the United Kingdom's model, further justify procedural tightening. The UK mandates accredited forensic standards under the Forensic Science Regulator Act, 2021, ensuring immediate sample assessments along strictly enforced chain-of-custody protocols. India’s guidelines, though narrower in scope, reflect a step towards similar accountability.

The Case Against Uniform Directives

Not all institutional actors endorse the Court’s intervention. Critics argue that procedural scripting across states assumes homogeneity in investigative capacity, which India’s federal structure does not support. Smaller states with limited FSL operational budgets may struggle to meet the mandated 48-hour submission window. What happens when FSLs themselves fail to function efficiently—six forensic labs in Bihar, for example, remained shut through late 2023 due to equipment shortages?

Moreover, procedural rigidities can inadvertently shift investigative priorities. Police personnel, instead of focusing on evidence-gathering in sensitive cases, may prioritize adherence to deadlines, turning logistical compliance into a substitute for investigative diligence. The broader critique lies in whether such judicial intervention constitutes a form of bureaucratic overreach. State governments, not the judiciary, bear responsibility for equipping and training investigators. Yet this framing obscures the tension between judicial oversight and state autonomy—a recurring fault line in India's federal governance.

Lessons from International Practice

The United Kingdom offers one notable counterpoint. Under its procedural guidelines, forensic firms must conform to strict regulatory standards, ensuring seamless integration across police forces, forensic labs, and legal mechanisms. Yet the UK has paired rigorous procedures with expansive funding—investments of nearly £150 million directly bolster lab capacity annually. That investment ensures timely analysis, mitigating concerns over sample degradation or backlogs.

In contrast, India's forensic infrastructure lacks comparable financial commitment. As of 2024, forensic sciences in India received a mere ₹635 crore, insufficient to fill toxicological and DNA-testing gaps across states. Without similar resource allocation, operationalizing the Supreme Court's guidelines risks reinforcing systemic inequities between wealthier states and those deprived of forensic expertise.

Where Things Stand

The Supreme Court has made commendable progress in addressing procedural weaknesses, but its guidelines expose structural gaps within India's criminal justice system. While ensuring timelines and chain-of-custody records is crucial, issues like FSL capacity constraints, state autonomy conflicts, and the uneven quality of investigations remain unresolved. The guidelines could set the tone for subsequent reforms; however, whether states will translate these judicial mandates into actionable strategy remains unclear.

Until forensic infrastructure receives scalable upgrades, these guidelines may be aspirational rather than transformative. The balance between judicial oversight and decentralized governance remains unsettled. The next question will be whether these procedural mandates — laudable on paper — survive India’s uneven federal implementation terrain.

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