Customs agency steps up controlled deliveries to nab drug smugglers

The Korea Customs Service (KCS) intercepted 5.6 kilograms of illicit drugs in 10 separate cases involving international mail from April to July through a newly established secondary screening network, the agency said Thursday.

In particular, it used controlled deliveries, a covert investigative technique, to track the shipments, resulting in the arrest of all suspects involved.

The new method involves a dual-layer drug screening system established in cooperation with Korea Post in April. Under the system, international mail that passes initial inspections at the border is subject to additional screening at one of five major postal distribution centers nationwide.

Central to the agency’s success in arresting all suspects was the strategic use of controlled deliveries, under which law enforcement officers deliberately allow intercepted parcels to proceed to their destinations while remaining under tight surveillance.

Because international mail allows authorities to maintain the normal delivery process without alerting traffickers, the tactic enables investigators to identify actual recipients and trace broader smuggling networks.

Timing remains the most critical variable in executing these operations, according to the agency, as any unusual delay in transit could tip off traffickers and prompt them to abandon the delivery location.

In one notable case, Seoul Regional Customs intercepted four cannabis cartridges concealed inside coffee bags being sent to a local hotel.

Working with other relevant agencies, investigators verified the arrival and hotel booking details of a U.S. national who had entered the country as a tourist. Officers carried out a controlled delivery directly to the hotel, where they apprehended the suspect just 24 hours after the drugs were initially detected.

Controlled deliveries generally take between two and three days to complete, but when a shipment is due to arrive the day after the drugs are intercepted, as in this case, swift information-sharing with relevant agencies is critical to launching the investigation, the agency said.

“We will continue to establish multi-layered defense lines across every entry route,” KCS Commissioner Lee Jong-wook said during a press briefing. “By using tactical measures like controlled deliveries, we will relentlessly pursue drug smugglers and their networks to root out threats to public safety.”

The crackdown reflects a broader government effort to strengthen border controls through multiple layers of enforcement.

Customs authorities have seized a total of 1,054 kilograms of illicit drugs in 954 cases through July. To support the crackdown, the agency has expanded its dedicated drug investigation force to 325 special judicial police officers across 39 specialized teams nationwide, more than tripling its personnel from about 100 officers last year. The expansion has been accompanied by heavy investments in digital forensics and cryptocurrency tracking.

Following its push into international mail inspection, the agency has rolled out additional interdiction networks for general commercial cargo and merchant vessel crews, while advancing plans to add extra screening layers for express shipments and international travelers.