Chain of Custody in Drug Cases: Why Gaps in Evidence Handling Can Lead to Acquittal

The Supreme Court's 2019 decision in People v. Labadan serves as a critical reminder that in drug cases, the prosecution must do more than prove a sale occurred—it must also account for every link in the chain of custody of the seized drugs. When police officers fail to explain gaps in evidence handling, even a seemingly solid buy-bust case can collapse.

The Case at a Glance

Edwin Labadan and Raquel Sagum were arrested in Quezon City on November 11, 2013, after allegedly selling 5.39 grams of methamphetamine hydrochloride ("shabu") to a poseur-buyer during a buy-bust operation. They were charged with violating Section 5, Article II of Republic Act No. 9165 (the Comprehensive Dangerous Drugs Act of 2002) and were convicted by both the Regional Trial Court and the Court of Appeals, each sentenced to life imprisonment and a fine of P500,000.00.

The Issue on Appeal

The accused appealed to the Supreme Court, arguing that the prosecution failed to establish the identity of the prohibited drug and to preserve its integrity and evidentiary value. Specifically, they pointed to gaps in the chain of custody—the procedure designed to ensure that the drugs presented in court are the exact same items seized from the accused.

The Chain of Custody Rule

Section 21 of RA 9165, as amended by RA 10640, requires that seized drugs be inventoried and photographed immediately after seizure in the presence of the accused or their representative, an elected public official, and a representative of the National Prosecution Service or the media. The rule also requires that the drugs be submitted to the forensic laboratory within 24 hours.

The Supreme Court has established that the prosecution must prove an unbroken chain of custody through four links: (1) seizure and marking by the apprehending officer; (2) turnover to the investigating officer; (3) turnover to the forensic chemist for examination; and (4) turnover and submission to the court.

Gaps in the Third and Fourth Links

In this case, the Court found the first two links sufficiently established. PO3 Diomampo marked the sachet at the arrest scene and later turned it over to investigator SPO2 Abad. However, the third link became problematic: the chain of custody document showed that SPO2 Abad returned the specimen to PO3 Diomampo, who then handed it to the forensic chemist. This was unusual—normally, the investigating officer directly turns over the evidence to the forensic chemist.

More troubling was an unexplained two-hour gap between 8:40 p.m. and 10:35 p.m. before the specimen was given to the forensic chemist. PO3 Diomampo offered no explanation for this delay or for how the specimen was handled to ensure its integrity during that time.

The fourth link also failed. Although the stipulation stated that the forensic chemist turned over the specimen to an evidence custodian after examination, the custodian's identity was never revealed, nor did that person sign the chain of custody document. The Court noted that no one testified about what happened to the specimen from the time of examination until it was presented in court.

Noncompliance with Witness Requirements

The Court also flagged the police officers' failure to comply with the witness requirements of Section 21. The marking of the specimen was done without any witness present, and the inventory was conducted only in the presence of a barangay kagawad—no representative from the media or the National Prosecution Service was secured.

While the law allows for noncompliance under justifiable grounds, the Court found the police officers' explanations insufficient. The buy-bust operation was planned in advance, giving the team ample time to ensure the presence of required witnesses. The Court cited People v. Alvarado, which rejected similar excuses for failing to secure DOJ and media representatives.

The Ruling

The Supreme Court acquitted Labadan and Sagum, holding that the prosecution failed to establish an unbroken chain of custody. The gaps in the third and fourth links, combined with the unexplained delay and the absence of required witnesses, cast serious doubt on whether the drugs presented in court were indeed the same items seized from the accused.

Practical Takeaways

• Every link matters. Police officers must be prepared to testify on each step of the chain of custody, including who handled the evidence, how it was stored, and any delays in turnover.
• Documentation is not enough. Signatures on a chain of custody form cannot substitute for actual testimony explaining what happened to the evidence at each stage.
• Plan for witnesses. In buy-bust operations, the team should secure the presence of required witnesses—an elected official, a DOJ representative, or media—before the operation begins, not after.
• Explain any delay. Unexplained gaps in time between seizure, inventory, and laboratory turnover can be fatal to the prosecution's case.
• For the accused and their counsel. Scrutinize the chain of custody carefully; gaps in evidence handling can be a strong ground for acquittal even when the sale itself appears proven.

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