He was a press officer for South Vietnamese President Ngô Đình Diệm.
[1] In 1963, during the Buddhist crisis, with relations between the United States and South Vietnam deteriorating, Khiêm drew up a hit list of American officials.
[2] In the September 1963 legislative elections, Khiêm stood for the National Assembly for a seat in Vĩnh Long,[3] which he subsequently won.
At the same time, he was estranged from his sister and her husband, who suspected him of handing over sensitive information about the government.
[7] In 1993, then 68, he was released from St. Elizabeths Hospital, when D.C. Superior Court Judge Curtis E. von Kann found that Khiem would never be competent to assist in his own defense.