Reasonable Doubt in Drug Cases: Why Strict Chain of Custody Matters

The Supreme Court's 2019 decision in People v. Sampa (G.R. No. 242160) acquitted an accused in a drug case because police officers failed to follow the strict procedural safeguards required by law. The case shows that even when a buy-bust operation results in an arrest and seizure, the prosecution must still prove that the drugs presented in court are exactly the same items seized from the accused. When the chain of custody is broken, reasonable doubt arises—and the accused must be acquitted.

The Facts of the Case

On February 24, 2014, PDEA agents conducted a buy-bust operation in Quezon City. The poseur-buyer purchased one plastic sachet of what tested positive as methamphetamine hydrochloride (shabu) from Jan Jan Tayan, with Aiza Sampa allegedly handing the drugs to him.

After the arrest, a commotion broke out when Tayan resisted. The team decided to leave the area immediately. The marking of the seized sachet was done inside the service vehicle, and the inventory and photographing were conducted later at the PDEA office in Camp Vicente Lim, Laguna—not at the place of arrest.

Only a media representative witnessed the inventory. No representative from the Department of Justice (DOJ) or any elected public official was present.

The Issue

The central question was whether the prosecution proved the accused's guilt beyond reasonable doubt despite the police officers' failure to comply with Section 21 of Republic Act No. 9165, the Comprehensive Dangerous Drugs Act of 2002, and its Implementing Rules and Regulations.

The Ruling: Acquittal on Reasonable Doubt

The Supreme Court reversed the conviction and acquitted Sampa. The Court held that the prosecution failed to establish the identity of the corpus delicti—the illicit drug itself—because of serious procedural lapses.

Marking Must Be Immediate

The Court reiterated that marking, or the affixing of initials and signature by the apprehending officer on the confiscated item, should be done immediately upon confiscation, in the presence of the apprehended person. In this case, the marking was done inside the service vehicle, not at the place of arrest.

The "Commotion" Excuse Was Insufficient

While the law allows marking and inventory at the nearest police station when immediate compliance is impracticable, the prosecution must prove the justifiable ground. Here, the alleged commotion was never detailed or corroborated. The Court noted that "commotion" is a convenient excuse often invoked by apprehending teams, but mere invocation does not amount to substantial compliance.

The Three-Witness Rule Is Mandatory

Section 21 requires the presence of three insulating witnesses during the physical inventory and photographing: (1) the accused or his representative or counsel, (2) a representative from the media, and (3) a representative from the DOJ and any elected public official.

The Court emphasized that these witnesses must be present not only during the inventory but, more importantly, at the time of the warrantless arrest. Their presence protects against the evils of switching, planting, or contamination of evidence. The PDEA agents made no honest effort to secure these witnesses—they did not even try to contact a DOJ representative.

The Saving Clause Did Not Apply

The "saving clause" in Section 21(a) of the IRR allows non-compliance only when there are justifiable grounds AND the integrity and evidentiary value of the seized items are properly preserved. Here, the prosecution failed to explain the deviations. The chain of custody was broken at its very inception—the marking—because no insulating witness was present to attest to it.

Practical Takeaways

• Chain of custody is not a mere technicality. It is a substantive safeguard that protects the accused from planting or tampering of evidence. A broken chain creates reasonable doubt.
• Marking, inventory, and photographing must be done immediately at the place of seizure. If impracticable, the nearest police station or office of the apprehending team must be used, and the justifiable ground must be proven.
• The three witnesses must be present at the time of arrest, not just at the inventory. Police cannot simply "call in" witnesses after the operation is finished.
• The "commotion" excuse will not save a weak case. The prosecution must present evidence of the commotion and the measures taken to preserve the integrity of the seized items.
• For accused persons and their lawyers: scrutinize the chain of custody. If the prosecution cannot explain deviations from Section 21, the proper remedy is acquittal.

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