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Supreme Court Guidelines on DNA Evidence in Criminal Cases

15 Sep 2025 GS 2 Polity
Supreme Court Guidelines on DNA Evidence in Criminal Cases Click to view full image

Why SC intervened

  • Case: Kattavellai @ Devakar v. State of Tamil Nadu (rape, murder, robbery).

  • In some cases (like rape and murder), police delayed sending DNA samples to labs.

  • The chain of custody (who handled the sample at each step) was unclear.

  • This raised doubts that samples might have been contaminated or tampered with.

  • So, the SC stepped in to make sure there is uniform procedure across India.

  • Problem: Different states, police, and labs follow no uniform procedure.

  • Reason for SC’s step: Ensure uniformity despite “Police” and “Public Order” being State subjects.

New Guidelines (2025)

Even though ‘Police’ and ‘Public Order’ are subjects mentioned in the State List of the Seventh Schedule of the Constitution, the Supreme Court deemed it necessary to issue these guidelines to have uniformity of procedure.

  1. Collection

    • Must be done with due care, proper packaging.

    • Label with FIR no., date, relevant sections/statutes, IO details, police station, serial no.

    • Documentation must include signatures/designations of:

      • Medical professional present

      • Investigating officer

      • Independent witnesses

  2. Transportation

    • investigating officer (IO) responsible for transporting DNA samples.

    • Must reach Forensic Science Laboratory (FSL) within 48 hours.

    • If delayed → reasons to be recorded; samples must be preserved properly.

  3. Storage

    • Samples pending trial/appeal cannot be opened, altered, or resealed without court authorisation.

  4. Chain of Custody Register

    • Maintained from collection → conviction/acquittal.

    • Must be appended to trial court record.

    • IO accountable for any lapses.

Supreme Court’s Stand on DNA Evidence (Past Rulings)

  • Anil v. State of Maharashtra (2014)

    • DNA reliable only if lab follows strict quality control.

  • Manoj & Ors. v. State of MP (2022)

    • DNA report rejected → samples recovered from open area, possibly contaminated.

    • Blood stains degraded, insufficient for testing.

  • Rahul v. State of Delhi (2022)

    • DNA rejected → remained in police Malkhana for 2 months.

    • Collection and sealing not free from suspicion.

    • Courts criticised for not examining reliability of DNA techniques used.

  • Devakar case (2025)

    • Stressed that procedural integrity outside the lab (collection, transport, custody) is as critical as lab procedure.

Importance & Limits of DNA Evidence

  • DNA = molecule carrying genetic info, obtainable from bone, blood, semen, saliva, hair, skin.

  • When crime scene DNA matches suspect → indicates common biological origin.

  • BUT:

    • It is opinion evidence under Section 45 of the Evidence Act / Section 39 of Bharatiya Sakshya Adhiniyam, 2023.

    • Its probative value depends on case-to-case basis.

    • Cannot alone be treated as conclusive; must be corroborated with other evidence.



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