Chain of Custody in Drug Cases: Why Witnesses and Marking Matter

In drug prosecutions, the seized substance is the very heart of the case. If its identity cannot be established with moral certainty, the accused must be acquitted. The Supreme Court, in People v. Esguerra (G.R. No. 243986, January 22, 2020), reaffirmed this principle and clarified what law enforcement must do to preserve the integrity of drug evidence — and why strict compliance with the chain of custody rule matters.

The Case: A Buy-Bust Operation in Butuan City

On March 18, 2010, operatives of the Philippine Drug Enforcement Agency (PDEA) conducted a buy-bust operation against R. Lorenz Esguerra y Baliber at his residence in Barangay Limaha, Butuan City. The poseur-buyer, Intelligence Officer 1 Myrian Aceron Balbada, recovered one plastic sachet containing white crystalline substance from Esguerra. The item tested positive for 0.0440 gram of methamphetamine hydrochloride, or shabu.

Esguerra was charged with Illegal Sale of Dangerous Drugs under Section 5, Article II of Republic Act No. 9165, the Comprehensive Dangerous Drugs Act of 2002. He denied the charge, claiming he was asleep when several men barged into his home, searched it, and arrested him without just cause.

The Regional Trial Court convicted him, and the Court of Appeals affirmed. Esguerra appealed to the Supreme Court, arguing that the identity and integrity of the seized drug were not properly preserved.

The Issue: Was the Chain of Custody Broken?

The central question was whether the prosecution had sufficiently established the chain of custody over the seized drugs. Esguerra argued that it had not, and that he should therefore be acquitted.

The Ruling: Conviction Affirmed

The Supreme Court dismissed the appeal and affirmed Esguerra's conviction. The Court held that the elements of Illegal Sale of Dangerous Drugs were proven: the identity of the buyer and seller, the object and consideration, and the delivery of the thing sold and the payment.

More importantly, the Court found that the chain of custody rule had been sufficiently complied with. The PDEA team conducted the marking, inventory, and photography of the seized item immediately after arrest, right at the place of arrest, in the presence of:

• Esguerra himself
• Barangay Captain Victor L. Abucejo (an elected public official)
• Media representatives Tootsie Licup and Rey M. Brangan
• DOJ representative Ronaldo T. Bedrijo

The seized item was then delivered to the crime laboratory for examination, and later brought to court for safekeeping, where it was presented, identified, and admitted as evidence.

The Chain of Custody Rule Explained

The Court reiterated that in drug cases, the dangerous drug itself forms an integral part of the corpus delicti — the body of the crime. The prosecution must account for each link of the chain of custody, from the moment of seizure up to presentation in court.

Under Section 21, Article II of RA 9165, the law requires that marking, physical inventory, and photography be conducted immediately after seizure. These must be done in the presence of the accused or his representative, plus certain witnesses. Before RA 10640 amended the law in 2014, the required witnesses were a media representative, a DOJ representative, and any elected public official. After the amendment, the requirement became an elected public official and either a representative of the National Prosecution Service or the media.

The presence of these witnesses serves a crucial purpose: it ensures the establishment of the chain of custody and removes any suspicion of switching, planting, or contamination of evidence.

Why Compliance Matters

The Court emphasized that failing to prove the integrity of the corpus delicti renders the evidence for the State insufficient to prove guilt beyond reasonable doubt, and warrants acquittal. This is why the chain of custody rule is not mere procedural formality — it is a safeguard against the grave injustice of convicting someone based on tampered or planted evidence.

Practical Takeaways

• Marking, inventory, and photography must be done immediately after seizure, ideally at the place of arrest or at the nearest police station or office of the apprehending team.
• The required witnesses must be present during inventory and photography. Before RA 10640 (effective August 7, 2014), these were a media representative, a DOJ representative, and an elected public official. After the amendment, an elected public official and a representative of the National Prosecution Service or the media.
• Every link in the chain must be accounted for — from seizure, to marking and inventory, to laboratory examination, to presentation in court.
• The accused or his representative must be present during the inventory and photography, unless the law's saving clause applies.
• For the defense, the chain of custody is often the strongest ground for acquittal. Gaps or unjustified deviations can create reasonable doubt.

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