Chain of Custody in Drug Cases: Ensuring Integrity of Evidence

The chain of custody rule is one of the most frequently contested issues in Philippine drug prosecutions. Under Republic Act No. 9165, the Comprehensive Dangerous Drugs Act of 2002, the prosecution must account for every link in the handling of seized drugs — from confiscation to laboratory examination to presentation in court. The purpose is simple: to ensure that the drugs presented as evidence are the very same items seized from the accused, and that their integrity has not been compromised.

In People v. Mohammad y Asdori (G.R. No. 213221, November 9, 2016), the Supreme Court had the opportunity to clarify when non-compliance with Section 21, Article II of R.A. No. 9165 may be excused, and why a belated objection to the chain of custody can be fatal to the defense.

The Buy-Bust Operation

The case arose from a buy-bust operation in Zamboanga City on June 23, 2005. Acting on a tip from a civilian informant, police officers conducted a buy-bust at a pension house. The poseur-buyer knocked on the door of Room 103, and accused Mina Ladjahasan answered. When the poseur-buyer said he wanted to buy P200.00 worth of shabu, Ladjahasan closed the door. Seconds later, her co-accused Biyan Mohammad opened the door, received the marked money, and handed over one sachet of suspected shabu.

After the pre-arranged signal was given, the team moved in. Mohammad was arrested and frisked, yielding the marked money and six more sachets of suspected shabu. Ladjahasan was also arrested, and a search of her shoulder bag yielded drug paraphernalia. The seized items were later tested and found positive for methamphetamine hydrochloride.

The Issue Raised on Appeal

Ladjahasan was convicted by the Regional Trial Court and the Court of Appeals for illegal sale of drugs and illegal possession of drug paraphernalia. On appeal to the Supreme Court, she raised two arguments.

First, she claimed that the prosecution failed to show her involvement in the sale. She argued that the only evidence against her was that she opened the door — which, she said, did not prove she participated in the transaction.

Second, she argued that the chain of custody rule was violated. She pointed out that the prosecution did not show where the marking of the seized items was done, how the items were handled during transport, and why no representative from the media, the Department of Justice, or an elected public official was present during the buy-bust.

Conspiracy May Be Inferred from Overt Acts

The Supreme Court rejected the first argument. The Court held that conspiracy can be deduced from the mode, method, and manner in which the offense was perpetrated. Here, the series of overt acts pointed to a common purpose: Ladjahasan screened the buyer at the door, and Mohammad completed the actual sale.

The Court quoted the Court of Appeals with approval: their modus operandi was for Ladjahasan to screen the buyer while Mohammad did the actual sale. Once conspiracy is established, a co-conspirator is liable as a co-principal regardless of the extent of her participation.

When Non-Compliance with Section 21 May Be Excused

On the chain of custody issue, the Court applied the ruling in People v. Ros (G.R. No. 201146, April 15, 2015). The Court noted that Ladjahasan raised the alleged non-compliance with Section 21 for the first time on appeal. During trial, she never questioned the handling and safekeeping of the seized items, nor did she move to quash the Information on that ground.

The Court explained that this omission is fatal. As it held in People v. Sta. Maria, when a party desires the court to reject evidence, the objection must be made at the proper time. An objection raised for the first time on appeal cannot be entertained.

The Court also reiterated the established doctrine that strict compliance with Section 21 is not always required. The arrest will not be invalidated, and the seized items will not be rendered inadmissible, solely because of non-compliance with the rule and its implementing rules. What matters most is the preservation of the integrity and evidentiary value of the seized items.

In this case, the prosecution was able to establish with moral certainty that the drugs and paraphernalia presented in court were the same items confiscated from the accused, tested, and found positive for a dangerous substance. The appeal was dismissed, and the conviction was affirmed.

Practical Takeaways

• Raise chain of custody issues at trial, not on appeal. An objection to the handling of seized evidence must be made before the trial court. Raising it for the first time on appeal is considered a waiver.
• Strict compliance is not absolute. The law excuses non-compliance with Section 21 under justifiable grounds. What is paramount is that the integrity and evidentiary value of the seized items are preserved.
• Conspiracy can be proven by conduct. In drug cases, a person who screens buyers or performs a supporting role can be held liable as a co-principal if the acts show a common design.
• Document every link in the chain. For law enforcement, proper marking, inventory, and turnover at every stage remain the best way to protect a case from attack.
• For the defense, act early. If there are gaps in the chain of custody, they should be explored during cross-examination and raised in the trial court's proceedings.

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