Reasonable Doubt in Drug Cases: Integrity of Evidence and Chain of Custody

In drug cases, the prosecution must prove not only that the accused sold or possessed illegal drugs, but also that the very drugs presented in court are the same ones seized from the accused. This requirement, known as the chain of custody rule, is a matter of substantive law. In People v. Dungo (G.R. No. 229720, August 19, 2019), the Supreme Court reversed a conviction for illegal sale of shabu because the prosecution failed to account for gaps in the chain of custody and did not justify deviations from the procedure required by Section 21 of Republic Act No. 9165 (RA 9165).

The Facts of the Case

In September 2009, police officers in Sto. Tomas, Pampanga conducted a buy-bust operation against a certain "Ogag," later identified as Melvin Dungo. A poseur-buyer handed P500 to Dungo, who gave two plastic sachets of suspected shabu in return. The arresting officer marked the sachets with the initials "JBL-1" and "JBL-2" at the scene. The items were later brought to the police station, where an inventory and confiscation report were prepared, and then to the PNP Crime Laboratory, which confirmed the substance was methamphetamine hydrochloride.

Dungo denied the charge, claiming he was arrested at his home without a buy-bust having occurred. The trial court convicted him, relying on the presumption of regularity in the performance of official duty. The Court of Appeals affirmed. The Supreme Court reversed.

The Issue: Proof Beyond Reasonable Doubt

The sole issue was whether the prosecution proved Dungo's guilt beyond reasonable doubt. The Court held that it did not. The identity of the dangerous drug is the corpus delicti of the crime, and it must be established with the same exactitude as every other element of the offense.

The Chain of Custody Rule Under Section 21, RA 9165

Section 21 of RA 9165 requires the apprehending team, immediately after seizure, to physically inventory and photograph the seized drugs in the presence of the accused (or his representative or counsel), a representative from the media, a representative from the Department of Justice (DOJ), and any elected public official. These witnesses must sign the inventory and receive copies.

The Court explained that the chain of custody has four links: (1) seizure and marking of the illegal drug by the apprehending officer; (2) turnover to the investigating officer; (3) turnover by the investigating officer to the forensic chemist; and (4) turnover and submission from the forensic chemist to the court. Every person who handled the evidence must describe how and from whom it was received, and what happened to it while in their possession.

Gaps in the Prosecution's Evidence

The Court found several fatal gaps in this case:

• No DOJ or media representative was present during the inventory at the police station, and the prosecution offered no justification for their absence.
• The barangay witnesses who signed the confiscation report — two kagawads — were never presented in court, and no explanation was given for their absence. The punong barangay who testified was not present during the inventory.
• The officer who delivered the drugs to the crime laboratory — PO2 Gonzales — was not part of the buy-bust team, did not testify, and the prosecution did not explain his role in the chain.
• The forensic chemist admitted he had no knowledge whether the sachets he examined were the ones actually sold by Dungo.

The Court stressed that the presumption of regularity in the performance of official duty cannot fill these gaps. That presumption stands only when no reason exists to doubt the regularity of official conduct, and it cannot prevail over the constitutional right to be presumed innocent.

Justifiable Non-Compliance Must Be Proven

The Court acknowledged that a perfect chain is not required and that Section 21 of the IRR allows for non-compliance under justifiable grounds. However, two elements must concur: (1) a justifiable ground for the deviation, and (2) proof that the integrity and evidentiary value of the seized items were preserved. These must be alleged and proven as facts by the prosecution — the court cannot presume their existence.

Because the prosecution in this case neither acknowledged nor justified the deviations, the saving clause did not apply. The Court also noted that the trial court itself found "badges of irregularity" in the prosecution's case yet still convicted based solely on the presumption of regularity.

Practical Takeaways

• The chain of custody is substantive law, not a mere technicality. Prosecutors must prove each link from seizure to court presentation with testimony from every person who handled the evidence.
• Marking is the starting point of the custodial link. It should be done immediately after seizure, and succeeding handlers must use the markings as reference.
• The three-witness rule is strict. The presence of the accused, an elected public official, and a DOJ or media representative during inventory is required, subject only to narrowly defined exceptions that must be proven.
• Non-compliance must be acknowledged and justified. The prosecution must expressly state the justifiable ground and the steps taken to preserve the evidence's integrity — mere invocation of the presumption of regularity is not enough.
• For the defense, gaps in the chain of custody — such as missing witnesses, unexplained turnovers, or a forensic chemist who cannot identify the seized items — can create reasonable doubt warranting acquittal.

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