'Faulty Investigation' : Supreme Court Acquits Man On Death Row, Issues Nationwide Guidelines On DNA Evidence Handling

The Supreme Court today (July 15) acquitted a man who was sentenced to death for the murders of a couple and the rape of the woman victim, citing grave procedural lapses in the handling of DNA evidence. In doing so, the Court issued binding nationwide guidelines to ensure proper collection, preservation, and processing of DNA and other biological materials in criminal investigations.

"A common thread that can be seen to be running through the entire process that has culminated by way of this judgment, is that of faulty investigation," the Court observed.

The case related to the murder of a couple in Tamil Nadu in 2021.

The bench comprising Justices Vikram Nath, Sanjay Karol, and Sandeep Mehta heard the case. The appellant Kattavellai @ Deevakar was sentenced to death by the trial court after being found guilty of the offences under Section 302, 376 and 397 of the Indian Penal Code. The conviction, which was affirmed by the High Court, rested almost entirely on circumstantial evidence, primarily the DNA match between biological samples collected from the crime scene and the accused.

Challenging the High Court's decision, the Appellant appealed to the Supreme Court, arguing systematic flaws in the police's investigation, particularly the handling, storage and forwarding of the DNA evidence.

Taking note of the material placed on record, the Court found multiple procedural deficiencies that rendered the DNA evidence unreliable. Notably, the Court pointed to the absence of a chain of custody register, unexplained delays in submitting samples to the forensic laboratory, and the lack of information on how the samples were stored, raising significant concerns about possible contamination or tampering.

Considering the sensitive nature of the DNA Evidence which is prone to dilution, the judgment authored by Justice Karol issued the following directives:

"1. The collection of DNA samples once made after due care and compliance of all necessary procedure including swift and appropriate packaging including a) FIR number and date; b) Section and the statute involved therein; c) details of I.O., Police station; and d) requisite serial number shall be duly documented. The document recording the collection shall have the signatures and designations of the medical professional present, the investigating officer and independent witnesses. Here only we may clarify that the absence of independent witnesses shall not be taken to be compromising to the collection of such evidence, but the efforts made to join such witnesses and the eventual inability to do so shall be duly put down in record.

2. The Investigating Officer shall be responsible for the transportation of the DNA evidence to the concerned police station or the hospital concerned, as the case may be. He shall also be responsible for ensuring that the samples so taken reach the concerned forensic science laboratory with dispatch and in any case not later than 48- hours from the time of collection. Should any extraneous circumstance present itself and the 48-hours timeline cannot be complied with, the reason for the delay shall be duly recorded in the case diary. Throughout, the requisite efforts be made to preserve the samples as per the requirement corresponding to the nature of the sample taken.

3. In the time that the DNA samples are stored pending trial appeal etc., no package shall be opened, altered or resealed without express authorisation of the Trial Court acting upon a statement of a duly qualified and experienced medical professional to the effect that the same shall not have a negative impact on the sanctity of the evidence and with the Court being assured that such a step is necessary for proper and just outcome of the Investigation/Trial.

4. Right from the point of collection to the logical end, i.e., conviction or acquittal of the accused, a Chain of Custody Register shall be maintained wherein each and every movement of the evidence shall be recorded with counter sign at each end thereof stating also the reason therefor. This Chain of Custody Register shall necessarily be appended as part of the Trial Court record. Failure to maintain the same shall render the I.O. responsible for explaining such lapse. The Directors General of Police of all the States shall prepare sample forms of the Chain of Custody Register and all other documentation directed above and ensure its dispatch to all districts with necessary instruction as may be required."

The Court directed the Registry to send a copy of this judgment to all High Courts and also the Directors General of the Police of all States to ensure necessary compliance.

Further, the Court also urged the Police Academies of the States to examine the necessity of conducting training of the Investigating Officers to ensure full compliance with the requisite precautions and procedures in accordance with the directions issued herein above.

The Square Circle Clinic, NALSAR University of Law, provided legal assistance to the appellant.

Cause Title: KATTAVELLAI @ DEVAKAR VERSUS STATE OF TAMILNADU

Citation : 2025 LiveLaw (SC) 703

Click here to read/download the judgment

Appearance:

For Appellant(s) Ms. V. Mohana, Sr. Adv. Ms. Manasa Ramakrishna, Adv. Ms. Sreepriya K., Adv. Mr. Mangesh Naik, Adv. Ms. Trisha Chandran, Adv. Mr. A. Karthik, AOR

For Respondent(s) :Mr. V Krishnamurthy, Sr. Adv. Mr. Sabarish Subramanian, AOR Mr. Vishnu Unnikrishnan, Adv. Ms. Azka Sheikh Kalia, Adv. Ms. Jahnavi Taneja, Adv. Mr. Veshal Tyagi, Adv. Mr. Danish Saifi, Adv.