Chain of Custody in Drug Cases: Why Procedural Lapses Lead to Acquittal

The Supreme Court has repeatedly emphasized that in drug cases, the prosecution must prove not only that the accused sold or possessed illegal drugs, but also that the seized items presented in court are the very same items confiscated from the accused. In People v. Sioson (G.R. No. 242686, July 7, 2020), the Court acquitted an accused because the police failed to comply with the mandatory chain of custody requirements under the Comprehensive Dangerous Drugs Act of 2002. The case serves as a reminder that procedural compliance is not mere formality—it protects the integrity of evidence and safeguards the accused from potential planting or tampering.

The Facts of the Case

On October 27, 2015, police operatives in Pilar, Bataan conducted a buy-bust operation against Zaldy Sioson based on a tip from a confidential asset. The poseur-buyer approached Sioson and purchased shabu worth P500.00. After the transaction, Sioson was apprehended, and four additional sachets of shabu were recovered from his pockets.

The police marked the seized sachets at the place of arrest with only Sioson present. The inventory and photography were conducted later at the police station, this time witnessed by representatives from the media, the Department of Justice, and a barangay official. The seized items tested positive for methamphetamine hydrochloride.

Sioson was convicted by the Regional Trial Court and the Court of Appeals. He appealed to the Supreme Court.

The Issue

The central question was whether the prosecution adequately complied with the chain of custody rule such that the identity and integrity of the seized drugs were preserved.

The Chain of Custody Rule

The chain of custody rule requires the apprehending team to conduct a physical inventory and photograph the seized items immediately after seizure and confiscation, in the presence of:

• The accused or his representative or counsel;
• An elected public official; and
• A representative of the National Prosecution Service or the media.

The inventory and photography must be done at the place of arrest, or at the nearest police station if that is more practicable. Non-compliance may be excused only if there are justifiable grounds, and the prosecution must prove that the integrity and evidentiary value of the seized items were properly preserved.

The Court's Ruling

The Supreme Court granted the appeal and acquitted Sioson. The Court found two serious breaches of the mandatory procedure:

First, the marking of the seized sachets was done at the place of arrest with only Sioson present. The required witnesses—an elected official and a representative from the National Prosecution Service or media—were not present during this crucial step.

Second, the inventory and photography were not conducted immediately at the place of arrest, but only later at the police station.

The prosecution offered no explanation for these deviations. The Court stressed that the prosecution has the positive duty to not only acknowledge but also justify any perceived deviations from the procedure. Since no justifiable grounds were proven, reasonable doubt was cast upon the integrity of the seized drugs.

The Court cited People v. Sood (G.R. No. 227394, June 6, 2018), which explained that the presence of the three insulating witnesses during seizure and marking protects against the pernicious practice of planting evidence. Without these witnesses, the evils of switching, planting, or contamination of evidence may negate the integrity and credibility of the seizure.

Practical Takeaways

• Marking is crucial. Marking sets apart and identifies the illegal drug from all other materials at the crime scene. The required witnesses must be present during this step.
• Immediacy matters. The inventory and photography should be done immediately after seizure, either at the place of arrest or at the nearest police station.
• Silence is fatal. If the police deviate from the chain of custody requirements, the prosecution must explain the deviation and prove justifiable grounds. Failure to do so can result in acquittal.
• The rule protects the accused. The insulating witnesses guard against the practice of planting evidence, which undermines the integrity of the corpus delicti.
• For law enforcement. Strict compliance with the chain of custody rule is not optional. Even if the accused is clearly guilty, procedural lapses can lead to the dismissal of the case.

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