The kingpin of the trafficking operation is believed to be 60-year-old Kimsoosik, a former South Korean police officer. He was arrested with accomplices in connection with a drug-trafficking case busted at the Cat Lai port in HCMC.

Drug squad officers from the military, cops under the Ministry of Public Security along with anti-smuggling investigation officials raided a 20-feet container Sunday and found 40 kilograms of meth hidden inside big granite blocks.

According to the customs declaration form, the granite had been disinfected before they were about to be exported to Incheon Port in South Korea.

While the trafficking operation was sophisticated, it was the first time investigators have found drugs hidden in construction rocks.

Kimsoosik, with more than 20 years in the Korean police force, had knowledge about such "tricks," the investigators said.

One of the investigators also said it was the first time they’d busted a drug trafficking operation involving both Korean and Chinese nationals.

The case is being investigated further.

Vietnam has some of the world’s toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or cocaine or over 2.5 kg of methamphetamine could face capital punishment.

The production or sale of 100 grams of heroin or 300 grams of any other illegal substance is also punishable by death.