The Seoul Metropolitan Police Agency said the Taiwanese obtained a screw making machine on a ship at a port in the southeastern coastal city of Busan, which departed from Bangkok on July 6 this year. Concealed inside the machine were 112 bags packed with 1 kilogram of methamphetamine each.

The customs authorities failed to detect the smuggled drug as it was concealed inside the machine and sealed up by welding. Usually, it is almost impossible for the customs authorities to detect drug smuggling attempts at a port, the Korea Customs Service said.

The customs office conducts drug inspections on only 2 percent of freight sent into South Korea and lacks the time to do more.

Sniffing dogs are of no use as methamphetamine has no color or smell, according to the office.

After the smuggling, the Taiwanese, along with a Taiwanese accomplice, transported the machine, sealed up by welding, to a warehouse in the city of Hwaseong, near Seoul, that he had rented prior to the smuggling. They took the machine apart to get hold of the drugs and stored them at an apartment in Seoul that he had also rented beforehand.

The Taiwanese transported 7 kilograms on July 29, 7 kilograms on July 31 and 8 kilograms on Aug. 18 of the drug to a Japanese dealer, who has yet to be arrested. The 34-year-old Japanese later sold the 22 kilograms of methamphetamine to the South Korean for 1.1 billion won.

After learning South Korean investigative authorities were moving to bust the syndicate, the Taiwanese attempted to exit the country on Aug. 26. He was arrested at Incheon airport, west of Seoul. The remaining 90 kilograms of the drug were confiscated.

The investigation into the drug smuggling case began in April this year, when the National Intelligence Service provided tips on a Taiwanese drug smuggling syndicates' storage of drugs in Seoul to the police agency and the customs service.

In August, the NIS informed the police that a Taiwanese hid methamphetamine at a coffee shop, which led to his arrest.

Police are chasing four main culprits who are believed to have given instructions to the six people. The police have secured arrest warrants for the four from their corresponding countries.

The drug smuggling involved affiliated groups of the Taiwanese syndicate Zhulianbang, or the Bamboo Union Gang, and the Japanese Inagawa-kai crime syndicate, police also believe. South Korean drug dealers, which have no connection with drug making organizations, are believed to have depended on the crime syndicates.

They have also asked the Thai police to track down the shipment details of the screw making machine to get leads on how the methamphetamine was smuggled. (Yonhap)