Nearly 12,000 bottles of illicit substances were confiscated during three joint operations conducted in Shenzen over the past month, according to the city’s Customs department.

Early on June 4 and June 6 officers from Shenzhen customs at Man Kam To Control Point and Futian Port intercepted three suspects, recovering 12 bottles, or 2,010ml, of codeine-laced cough syrup, the Paper reported quoting Xinhua.

Codeine is the main ingredient in cough syrup and classified as a mild opioid narcotic and an illegal drug in mainland China. People allegedly use it when seeking a narcotic high.

A special team of investigators from Shenzhen Customs’ smuggling suppression bureau and the Narcotics Control department under the city’s bureau of public security identified a gang headed by a man surnamed Chen, who was allegedly notorious for smuggling, transporting and trafficking codeine-laced cough syrup.

After investigations and intelligence gathering, Customs officers and police raided a premises in Bao’an district in Shenzhen city on July 17, where Chen and two accomplices were arrested.

Based on their confessions and information, a warehouse in Jieyang – a city in Guangdong Province – was raided, where 84 cartons, or 11,915 120ml bottles of illegal foreign-imported cough syrup were taken as evidence.

Customs’ preliminary investigation found that the syndicate was hiring individual visitors and deploying cross-boundary mainland vehicles to smuggle cough syrup from Hong Kong to Shenzhen.

These individuals were mainland Chinese aged between 20 and 30 and holders of two-way permits for travel to and from Hong Kong and Macau. In order to evade detection by Customs, the smuggled bottles were hidden in packages of personal care products or boxes for wine.

Shenzhen authorities said they would continue to investigate this problem with local officials.