The People's Supreme Procuracy, Vietnam's highest prosecutors' office, has charged two Filipinos with "illegally trafficking drugs", an offence punishable by death.
According to the indictment, Raquel Malayano Ramos, 32, was arrested on August 8, 2009 when she was receiving heroin from a person named Shane in Cambodia's Long Beach Plaza.
Raquel was hired by another person named Elsa to bring heroin from Cambodia to Vietnam for US$3,000.
Cambodian police later handed Raquel and the evidence over to Vietnamese police.
John Lopez Diemsen, 48, who introduced Raquel to Elsa, was arrested three days later at a bus station in Vietnam's southern province of Tay Ninh. He was nabbed while receiving a bag containing 842.2 grams of heroin, inspectors said.
Vietnam has some of the world's toughest drug laws. Those who smuggle more than 600 grams of heroin into the country can be sentenced to death.