Chain of Custody in Drug Cases: Why Unbroken Evidence Integrity Matters

The integrity of seized evidence can mean the difference between conviction and acquittal in Philippine drug cases. In People v. Nazareno (G.R. No. 174771, September 11, 2007), the Supreme Court reversed a life imprisonment sentence because the prosecution failed to establish an unbroken chain of custody over the alleged shabu. The ruling reminds law enforcers and prosecutors that proving guilt requires more than just testimony—it requires showing that the drugs presented in court are exactly the same items seized from the accused.

The Facts of the Case

On September 15, 2003, police operatives in Iligan City conducted a buy-bust operation against Allan Nazareno, who was suspected of selling shabu. PO2 Magno, acting as poseur-buyer, purchased two sachets of shabu for P200.00 from Nazareno inside his beauty parlor. After the pre-arranged signal, the team arrested Nazareno and recovered the marked money from his person.

The two sachets were later examined by P/S Inspector Bernido, a forensic chemist, who confirmed they contained methamphetamine hydrochloride. The trial court convicted Nazareno of illegal sale of drugs under Section 5, Article II of Republic Act No. 9165, sentencing him to life imprisonment and a fine of P500,000. The Court of Appeals affirmed, but the Supreme Court reversed.

The Issue: Was the Corpus Delicti Properly Established?

For a conviction for illegal sale of dangerous drugs, the prosecution must prove three things: (1) the transaction or sale actually took place; (2) the corpus delicti or the illicit drug was presented as evidence; and (3) the buyer and seller were identified.

In this case, the Court found that while the police officers identified Nazareno as the seller, the prosecution failed to prove the existence of the corpus delicti—the very drug itself—because the chain of custody was broken.

The Broken Chain of Custody

The Court highlighted several critical gaps in the prosecution's handling of the seized drugs:

No immediate marking. PO2 Magno admitted he did not mark the two sachets upon recovery, despite having been trained to do so. He simply handed them to SPO2 Lluisma, who was not presented as a witness.

Unknown origin of markings. When the forensic chemist received the sachets, they were already marked "A-01" and "A-02" and placed in a plastic bag bearing Nazareno's name. However, no one testified as to who actually made these markings or where they were made.

Missing witness. SPO2 Lluisma, the officer who received the drugs from PO2 Magno, was never presented in court. He was in the best position to testify on what happened to the drugs after the arrest, but the prosecution failed to explain his absence.

No inventory. There was no evidence that an inventory of the seized items was conducted as required by procedure.

Why This Matters: Presumption of Regularity vs. Reasonable Doubt

The Court rejected the prosecution's reliance on the presumption of regularity in the performance of official duties. Citing People v. Lim, the Court held that failure to comply with proper custody procedures raises doubt about whether the drugs submitted for laboratory examination and presented in court were actually the same items recovered from the accused. This doubt negates the presumption of regularity.

The Court also cited People v. Laxa and Zarraga v. People, where similar deviations from standard procedure led to acquittals. The message is clear: when the chain of custody is broken, the identity of the corpus delicti becomes uncertain, and the accused must be acquitted on reasonable doubt.

Practical Takeaways

• Mark evidence immediately. Police officers must mark seized drugs at the scene, in the presence of the accused, to establish a clear link between the accused and the drugs.
• Document every transfer. Every person who handles the evidence must be presented or accounted for, from the arresting officer to the forensic chemist.
• Conduct a proper inventory. Seized drugs should be physically inventoried and photographed in the presence of the accused or a representative, who should sign the inventory.
• Present all key witnesses. The prosecution cannot rely on the presumption of regularity if it fails to present the officer who had initial control of the drugs.
• For the accused, challenge the chain. Defense counsel should scrutinize the prosecution's evidence-handling procedures, as gaps can create reasonable doubt sufficient for acquittal.

The Nazareno case underscores that in drug offenses, the drug itself is the crime. If the prosecution cannot prove with moral certainty that the drugs presented are the same ones seized, the constitutional presumption of innocence prevails.

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