According to investigators, Um Youn Min, 45, was member of a ring that manufactured methamphetamine and organized parties in which attendants would be offered different types of narcotics.
South Korean police busted the ring and arrested many members, but Um fled to Vietnam.
Ho Chi Minh City police tracked him down and arrested him in the city.
According to South Korean drug laws, its nationals are not allowed to consume drugs, regardless of their geographical location, including in nations where drug use is lawful.
For example, South Korean citizens are explicitly banned from consuming cannabis, even when they are in countries that have legalized or decriminalized its use.