Some commentators contend that Sam Sary worked with U.S. intelligence services, which he might have contacted in 1956 while visiting the U.S. On 13 January 1959, in a speech delivered in Kampong Cham, Sihanouk told his listeners that he knew about U.S. intelligence plots to overthrow him. While this speech had not clearly implicated Sam Sary, a week after the speech was delivered, he fled to Thailand. After a shadowy existence in exile, he disappeared in 1962. His son Sam Rainsy asserts that his father was killed in Pakse, Laos on the orders of Son Ngoc Thanh in late 1962 or early 1963.