A Ho Chi Minh City court delayed a trial of 15 Vietnamese gang members who smuggled drugs from Cambodia to Vietnam, on Tuesday.
The delay came shortly after a lawyer informed HCMC People's Court judges that one of the defendants, Nguyen Van Binh, is a Cambodian national.
The judges said the revelation would require city prosecutors to open a fresh investigation into the case.
The defendants were arrested between July 2007 and August 2008 for transporting drugs from Cambodia to Vietnam, through the southwestern border, and selling them in HCMC and Vung Tau.
According to the indictment, the gang smuggled a huge quantity of heroin and ecstasy tablets from Cambodia to Vietnam between 2005 and 2007.
Nguyen Tan Duy, the ringleader, used to serve as a guard at Xuyen Moc Prison in Ba Ria-Vung Tau Province. After he quit the job in 1994, prosecutors say he returned to the prison and helped Le Hoang Hoi, who was then serving a 15-year jail term for robbery, to escape.
Prosecutors said that the two men put together a drug smuggling crew after they arrived in Cambodia.