Chain of Custody in Drug Cases: When Broken Links Lead to Acquittal

The chain of custody rule is one of the most important safeguards in Philippine drug cases. It ensures that the illegal drugs seized from an accused are the very same items presented in court. When police officers break this chain, the prosecution fails to prove its case, and the accused must be acquitted. In People v. Kasan y Atilano (G.R. No. 238334, July 3, 2019), the Supreme Court demonstrated exactly how strictly this rule is applied.

The Case Before the Court

Roseline Kasan and Henry Llacer were arrested in Makati City on December 10, 2015, during a buy-bust operation. Police claimed Kasan sold 0.18 gram of methamphetamine hydrochloride (shabu) to a poseur buyer for P500, and that Llacer was found possessing another 0.09 gram. They were charged with illegal sale of dangerous drugs under Section 5 of Republic Act No. 9165, and Llacer was separately charged with illegal possession under Section 11.

The Regional Trial Court convicted both accused. The Court of Appeals affirmed the conviction. On appeal, the accused argued that police committed serious procedural lapses in handling the seized drugs.

The Chain of Custody Rule

In illegal drug cases, the drug itself is the corpus delicti — the body of the offense. The prosecution must prove that the substance seized from the accused is the same substance examined by the forensic chemist and later presented in court. This is done by establishing every link in the chain of custody.

The chain has four links: (1) seizure and marking of the drug by the apprehending officer; (2) turnover to the investigating officer; (3) turnover by the investigating officer to the forensic chemist for examination; and (4) turnover and submission of the marked drug by the forensic chemist to the court.

The Breaches Committed by Police

The Supreme Court found several serious violations of the chain of custody rule in this case.

First, the seized drugs were not marked, inventoried, or photographed at the place of arrest. The police brought the accused first to the barangay hall of Brgy. Olympia, then to Brgy. West Pembo because no barangay official was available. The items were only marked two hours after the arrest. The police claimed "security reasons" justified the delay, but they never explained what those reasons were. The Court rejected this bare allegation, noting that the two-hour gap exposed the drugs to switching, planting, and contamination.

Second, only one witness — a barangay kagawad — was present during the inventory and photographing. Section 21 of RA 9165, as amended by RA 10640, requires the presence of an elected public official and a representative of the National Prosecution Service or the media. The police did not even attempt to explain why they failed to secure the other required witness.

Third, the parties stipulated to dispense with the testimony of the forensic chemist, but the stipulation did not cover how she received, handled, and preserved the seized drugs. The Court held that such stipulations must include that the chemist received the item as marked, properly sealed, and intact; resealed it after examination; and placed her own marking on it.

Fourth, no witness testified on how the drugs were brought from the crime laboratory to the trial court. This broke the fourth link in the chain.

The Presumption of Regularity Cannot Save the Prosecution

The Court emphasized that the presumption of regularity in the performance of official duties cannot substitute for actual compliance with the chain of custody rule. It is a mere disputable presumption that cannot prevail over clear evidence of repeated breaches.

The Court also noted that the saving clause in the law — which allows leniency when there are justifiable grounds for non-compliance — did not apply because the prosecution failed to prove any justifiable ground and failed to show that the integrity of the seized items was preserved.

Practical Takeaways

• Mark drugs immediately. Seized items should be marked, inventoried, and photographed at the place of arrest or as soon as practicable. Any delay must be justified with concrete reasons, not vague claims of "security reasons."
• Secure all required witnesses. The presence of an elected public official and a representative of the National Prosecution Service or media is mandatory. Police must exert genuine efforts to secure these witnesses and must explain any failure.
• Document every transfer. Each link in the chain — from arresting officer to investigator to forensic chemist to court — must be accounted for with clear testimony.
• Stipulations must be complete. When parties agree to dispense with a forensic chemist's testimony, the stipulation must cover the handling, storage, and preservation of the seized drugs.
• Presumption of regularity is not a shield. Police cannot rely on the presumption of regular performance of duty to excuse broken links in the chain of custody.

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