Dr. Trần Kim Tuyến (1925–1995) was the chief of intelligence of South Vietnam under its first President Ngô Đình Diệm from 1955 to 1963. As a Roman Catholic, he was trusted by the Ngô family, and was part of their inner circle. Tuyến was responsible for a variety of propaganda campaigns against communists, and was prominent in operating the secret Cần Lao party apparatus which maintained the Ngô family's rule. In the course of his work, Tuyến emulated the tactics of the communists. He eventually became disillusioned and plotted against the regime before being exiled. After Diệm was deposed, Tuyến returned to South Vietnam, but the military junta which had replaced the Ngô family jailed him for five years. He fled the country in 1975 as Saigon was falling.
Tuyen hailed from Phát Diêm, Ninh Bình, Vietnam, French Indochina. He studied at the French-founded university in Hanoi, obtaining degrees in law and medicine. As a university student, he had protested against the French colonial administration's control over Vietnam's Catholic clergy, landing him in trouble with the police.