The Ho Chi Minh City prosecutor's office has charged 10 people in a gang busted last year with dealing drugs.
According to the indictment, Dao Nguyen Long, 50, was running a restaurant in District 3 when he met Nguyen Thi Kieu Thu, 43, and began to buy synthetic drugs from her.
He also bought drugs from Nguyen Tan Cuong, 47, and an unidentified Cambodian, to sell to others, prosecutors said.
By the time the gang was caught in September last year, it had sold 585 grams of heroin, including more than 158 grams of methamphetamine smuggled in from Cambodia.
Vietnam has some of the world's toughest drug laws, with those convicted of smuggling more than 600 grams of heroin facing the death sentence.