Chain of Custody in Drug Cases: A Guide to Ensuring Evidence Integrity

In every prosecution for illegal drugs under Republic Act No. 9165, the prosecution must do more than prove that a sale or possession occurred. It must also establish, beyond reasonable doubt, that the drugs presented in court are the very same items seized from the accused. This is the essence of the chain of custody rule. The Supreme Court's decision in People v. Somira (G.R. No. 252152, June 23, 2021) provides a clear illustration of how this rule works and when deviations from the prescribed procedure may still be excused.

The Case: A Buy-Bust Operation Gone Crowded

In June 2015, PDEA agents conducted a buy-bust operation against Mila Somira in Pasay City. A poseur-buyer purchased approximately 1,099.66 grams of shabu from her at a restaurant inside a shopping mall. Upon arrest, Somira became hysterical and drew a crowd. To avoid commotion, the team brought her to the PDEA office in Quezon City, where the marking and inventory of the seized drugs were conducted—not at the place of arrest.

Somira was charged with illegal sale of dangerous drugs under Section 5, Article II of RA 9165. She was convicted by the Regional Trial Court, and the Court of Appeals affirmed. On appeal, the Supreme Court upheld her conviction.

The Issue: Was the Chain of Custody Broken?

Somira argued that the prosecution failed to prove an unbroken chain of custody and to comply with the mandatory requirements of Section 21, Article II of RA 9165, as amended by RA 10640. The Court disagreed.

The Ruling: Substantial Compliance, Properly Justified

The Supreme Court laid down the four links that must be established in a buy-bust situation:

1. Seizure and marking of the illegal drug by the apprehending officer;
2. Turnover of the seized drug to the investigating officer;
3. Turnover by the investigating officer to the forensic chemist for laboratory examination; and
4. Turnover and submission of the marked drug from the forensic chemist to the court.

In Somira, the marking and inventory were done at the PDEA office, not at the place of seizure. The Court found this to be a justified deviation. The buy-bust took place in a crowded mall, and the accused was hysterical and resisting arrest. Conducting the inventory there would have been impractical and unsafe. The inventory was instead conducted in the presence of the accused, a barangay official, and a media representative—satisfying the witness requirement under Section 21.

The Court also noted that the apprehending officer kept sole custody of the seized item until she personally delivered it to the forensic chemist, who then turned it over to the court. The marking "EXH A-2 RGS 6/22/15" was made by the officer herself. No gap in custody was shown, and the accused presented no evidence of tampering or switching.

The Rule on Non-Compliance

The Court reiterated that non-compliance with Section 21 will not automatically invalidate the seizure and custody of drugs. Two conditions must be met: (1) there is a justifiable ground for the non-compliance, and (2) the integrity and evidentiary value of the seized items are properly preserved. Absent these, non-compliance becomes a "red flag" that casts reasonable doubt on the identity of the corpus delicti.

Practical Takeaways

• Mark immediately. Marking the seized item at the earliest opportunity is the starting point of the chain. Delayed marking must be justified.
• Know the witness requirement. Under RA 10640, the inventory must be witnessed by an elected public official and a representative of the National Prosecution Service or the media. Their signatures are required.
• Justify every deviation. If the inventory is not done at the place of seizure, the prosecution must explain why. Public safety and crowd control can be valid grounds.
• Document every transfer. Every person who handles the evidence should be identified, and the transfer should be recorded—whether through an acknowledgment receipt or other means.
• For the defense: A mere allegation of a broken chain is not enough. There must be proof of tampering, switching, or unjustified non-compliance that casts real doubt on the identity of the drugs.

This article is general information and not legal advice. For your specific situation, consult a lawyer or ask ASG Legal AI.