Chain of Custody in Drug Cases: Why Every Link Matters After People v. Tumangong

The Supreme Court’s 2018 decision in People v. Tumangong is a clear reminder that in drug cases, proving the crime is not enough—the prosecution must also prove that the seized drugs presented in court are the same items taken from the accused. When police officers fail to follow the chain of custody rules under Republic Act No. 9165, the case collapses, even if the accused was caught in the act.

This article explains the case, the rules on chain of custody, and what the ruling means for law enforcement and accused persons.

The Facts of the Case

On September 13, 2011, police officers in Taguig City conducted a buy-bust operation against Fatima Tumangong after a confidential informant reported that she was selling drugs. A poseur-buyer purchased 0.30 gram of shabu from her using marked money. After the transaction, the officers arrested her and marked the seized plastic sachet at the scene.

The prosecution presented the arresting officers, who testified that they tried to secure the presence of barangay officials and a Department of Justice representative but failed. No photographs were taken of the seized item. The drugs were eventually turned over to an investigator and then to the crime laboratory, where a forensic chemist confirmed the substance was methamphetamine hydrochloride.

The trial court convicted Tumangong, and the Court of Appeals affirmed. She appealed to the Supreme Court.

The Issue

The central question was whether the prosecution had established an unbroken chain of custody over the seized shabu, as required by Section 21 of RA 9165. The defense argued that the police failed to comply with the mandatory procedure, compromising the integrity of the evidence.

The Ruling

The Supreme Court reversed the conviction and acquitted Tumangong. The Court held that the prosecution failed to prove every link in the chain of custody, which is essential to establish the identity and integrity of the seized drugs.

The Court identified four links in the chain:

1. Seizure and marking — the apprehending officer must mark the seized item at the place of arrest, if practicable.
2. Turnover to the investigating officer — the apprehending officer must transfer custody to the investigator.
3. Turnover to the forensic chemist — the investigator must deliver the item to the crime laboratory for examination.
4. Turnover to the court — the forensic chemist must submit the item and the examination report to the court.

In this case, the investigator who received the drugs from the arresting officer and the crime laboratory personnel who received the specimen were never presented in court. The forensic chemist's testimony was also dispensed with by stipulation. The Court stressed that every person who touches the seized item must testify on how it was handled and preserved while in their custody.

The Court also noted that the police failed to comply with Section 21's requirement to conduct the inventory and photograph the seized item in the presence of an elected public official, a representative of the DOJ, and a representative of the media. The arresting officer's excuse—that he had no camera—was rejected as a "lame" justification.

Why This Matters

The ruling reinforces the principle that the presumption of regularity in the performance of police duties is not absolute. When officers deviate from the prescribed procedure, that presumption is destroyed, and the prosecution must offer justifiable reasons for the non-compliance.

The Court also reminded lower courts to exercise a higher level of scrutiny in cases involving miniscule amounts of drugs, because the small quantity makes tampering or substitution easier.

Practical Takeaways

• Chain of custody is not a technicality. It protects the accused from planted or substituted evidence. A broken chain can lead to acquittal even when the sale was witnessed.
• Every link must testify. The arresting officer, the investigating officer, the crime laboratory personnel, and the forensic chemist must each describe how they received, handled, and preserved the seized item.
• Compliance with Section 21 is mandatory. Marking, inventory, and photographing must be done in the presence of the accused and the required witnesses—an elected official, a DOJ representative, and media—unless there is a justifiable reason for non-compliance.
• Weak excuses will not save the case. Saying "we had no camera" or "no barangay official came" is not enough. The police must show genuine efforts to secure the presence of the required witnesses.
• For accused persons and their lawyers, scrutinize the chain of custody carefully. Gaps in testimony or documentary evidence can be the basis for an acquittal.

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