Hong Kong police and customs officers have confiscated cocaine worth HK$390 million (US$49.9 million) in a marshmallow shipment from South America, the biggest seizure of the drug this year.

Senior Inspector Chu Siu-lun of police’s narcotics bureau on Thursday said two men – a city resident and an Ecuadorean – were arrested after sneaking into a cargo vessel to allegedly guard the 318kg (about 700 pounds) cocaine haul hidden in some of the Asia-bound containers on board.

The drugs were sealed in nine waterproof bags attached to life jackets and inflated buoys inside a shipping container and were scheduled to be offloaded from a cargo vessel in Jordan, he added.

“Based on our preliminary investigation, there is no evidence to prove that the seized drugs were intended for Hong Kong.”

Police say cocaine haul was discovered after receiving a report of two men being on board a Hong Kong-registered cargo ship. Photo: Jelly Tse

But Superintendent Wilson Tam Wai-shun said he believed the transnational drug trafficking syndicate arranged for the two men to secretly board the ship to keep an eye on the drugs.

“We believe the nine bags containing the drugs would have been thrown into the sea, had the ship reached the target maritime area [in the Asian region],” he said. “The two men or others would have put on diving suits or life jackets, go into waters [to retrieve the bags] and then wait for a boat to pick them up,” he said.

The two men, aged 19 and 24, remained in police custody on suspicion of drug trafficking – an offence punishable by up to life in jail and a HK$5 million fine.

On November 1, police received a report of two men, who were not crew members, being on board a Hong Kong-registered cargo ship after it left a port in Mexico en route to Asia.

The crew then reported the incident to Hong Kong police via a shipping agency, according to the force.

The vessel left Guatemala for Mexico via Ecuador, Peru and Panama and was scheduled to go to Hong Kong before leaving for Jordan.

Chu said an investigation suggested the two men might have brought prohibited items, such as illegal drugs, onto the ship.

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As the cargo vessel was carrying many containers, police sought help from customs officers to conduct a joint operation.

Before the arrival of the vessel, Assistant Superintendent Alex Wong Kei-cheung of customs’ containerised cargo examination division said they studied shipping documents and identified a shipment of three containers declared to have carried marshmallows.

When the cargo vessel berthed at Kwai Chung container terminal on Tuesday afternoon, officers boarded the ship and selected the three containers for inspection.

Wong said X-ray examination of one of the containers showed suspicious images and it was then towed to the Kwai Chung Customhouse for further inspection.

“We discovered vacuum-sealed packets of white powder in the [nine] bags. Samples then tested positive for cocaine,” he said

Wong said the haul of suspected cocaine had an estimated street value of HK$390 million.

Two arrested after authorities find the drugs sealed in nine waterproof bags in a shipping container. Photo: Jelly Tse

Police said an investigation was under way and did not rule out further arrests.

Superintendent Tam pledged to make every effort to combat transnational drug trafficking activities and identify the possibility of illegal drugs passing through Hong Kong.

He said police and customs would continue to enhance intelligence sharing and take appropriate actions to fight drug trafficking.

This is the third major drug seizure by local authorities in the past few weeks.

On November 1, customs officers seized about HK$140 million worth of illegal drugs hidden in a shipment of machine parts from North America.

On October 26, customs officers made their biggest seizure of crystal meth in solid form after discovering a haul worth HK$640 million in a shipment of snail shells from Mexico.