The Cambodian Communist movement was rooted in the anti-French struggle which played out between 1946 and 1954. This period is sometimes referred to as the First Indo-China War. Before World War II, nearly all the Communists in Cambodia (and there were very few of them at the time) were ethnic Vietnamese. Under Vietnamese guidance, a fledgling Cambodian Communist party was formed in 1951. Initially, its members were particularly active in rural areas bordering Vietnam, and helped Viet Minh forces engaging the French in Vietnam. The leaders of the small Cambodian party were fluent in Vietnamese and received ideological and practical training from Vietnamese cadres, who emphasized solidarity between “Indo-Chinese” people. Members and sympathizers tended to be poor peasants from areas bordering Vietnam. Little fighting occurred in Cambodia itself, where the popular monarch, Norodom Sihanouk, was pro-French and soon co-opted the leadership of the non-Communist opposition to France.
Cambodia gained its independence in 1953, and national elections were held two years later. A Communist front party won 30,000 votes, mainly from the eastern part of the country, but the candidates selected by Sihanouk for his new political movement, the Sangkum Reastr Niyum, won all the seats in the National Assembly. In response to this defeat, rural Communists then laid down their arms and, without repenting for the past, abandoned politics. Those in the cities led a clandestine existence, harassed by Sihanouk’s police and isolated from their distant and indifferent patrons in Hanoi.
In the early 1960s, a group of Communists who had studied for a time in France, including Saloth Sar (who was later known as Pol Pot) took command of the urban Communist movement and renamed it the Workers’ Party of Kampuchea (WPK). The leader of the movement, Tou Samouth, disappeared in 1962, presumably killed by Sihanouk’s police. In 1963 Saloth Sar, Samouth’s replacement, fearing arrest, took refuge with several colleagues in a secret Vietnamese Communist base on the Cambodian-Vietnamese border. In the meantime, the Second Indo-China War intensified as hundreds of thousands of US troops entered the civil war being fought in southern Vietnam. In late 1965 Saloth Sar was summoned to Hanoi to discuss the war, and more specifically, the role that Cambodian Communists might play in it. He also traveled to China, where he was impressed by the radicalism of the early stages of the Cultural Revolution. Returning to Cambodia, he relocated his headquarters to the remote Northeast of Cambodia, renamed his party the Communist Party of Kampuchea (CPK) and, along with a few hundred followers, plotted to seize power.
When Sihanouk was overthrown in a bloodless coup in March 1970, the CPK joined forces with the Vietnamese Communists to defeat the new, pro-American regime in Phnom Penh. The Vietnamese withdrew their forces at the end of 1972. By then the Khmer Rouge had developed into a formidable fighting force, led from the shadows by Saloth Sar and a group of trusted military commanders.
In April 1975 Khmer Rouge forces entered Phnom Penh, and almost immediately the city’s entire population was forced into the countryside to become agricultural workers. Saloth Sar and his colleagues came to the city a few days later and established the rudiments of an administration. To appease international opinion, the new regime, now calling itself Democratic Kampuchea, promulgated a constitution in January 1976, which failed to mention the country’s Communist affiliations, and pushed ahead with a collectivization program modeled on those in force in China. The new regime’s leaders were suspicious of Vietnam and fearful that a range of enemies were conspiring to destroy DK. In a series of purges in 1975 thousands of men, who had been part of the defeated Cambodian army, were executed secretly along with high officials of the former regime.
In May 1976, after thwarting what it mistakenly considered to be an attempted coup, the leaders of DK established a secret detention and interrogation facility located in a former high school in the Tuol Sleng district of Phnom Penh, and gave it the code name S-21. A previous, smaller facility had already been in operation for about a year in the suburb of Ta Khmau. Prisoners held in Ta Khmau had primarily been former officials and soldiers connected with the defeated regime, and several of them were released after interrogation. The new facility was intended primarily for enemies of the state (khbot cheat) who were almost always associated with DK. Purges swept successively through the northern and north-western zones in 1977, and through the eastern zone bordering Vietnam in 1978 - the year in which war broke out between DK and Vietnam. Other purges took place in military units, government bureaus and factories once ranking officials in these facilities came under suspicion.
Before S-21 was abandoned in January 1979, in the wake of a Vietnamese invasion, over 15,000 men women and children were detained there; they were photographed, interrogated, and in many cases, severely tortured before being put to death. None of the prisoners were released, only one is known to have escaped, and only a dozen survived.
Interrogation centers and prisons also existed in other parts of Cambodia, and it seems likely that tens of thousands of prisoners were tortured and put to death in these facilities as well. The difference between the regional prisons and S-21, aside from the fact that many people were released from regional prisons, was that S-21 was reserved almost entirely for people accused of betraying DK from the “inside” through espionage or other treacherous activities. Many of the prisoners at S-21 were high-ranking party cadres, and they were interrogated over several weeks. In the closing months of DK over one hundred Vietnamese prisoners of war were also interrogated and executed at S-21.
Because of its enormous archive of “confessions” and photographs, and because the site was turned into a Museum of Genocidal Crimes in 1980, S-21 is the best known and most visible institution that survives from DK. Certainly the prison and the documents it produced encapsulate the regime’s absolute power over life and death, its ruthlessness and its perhaps only partially mistaken belief that its enemies were everywhere. The museum is now a popular tourist destination.