Preap In

In was executed by firing squad at Trapeang Kraleung, Kampong Speu Province, in January 1964.

A high-level cadre of the Khmer Serei, a rightist militia formed to oppose the regime of Prince Norodom Sihanouk, In is remembered largely for an unsuccessful 1963 attempt to 'negotiate' directly with Sihanouk, resulting in his arrest and public execution by firing squad.

Preap In and an associate, Saing San (described as a chauffeur at the Royal Palace) were arrested in Takeo on 19 November 1963; they were brought to Phnom Penh and displayed in cages in public. Although San was soon to be released, In was brought before the National Assembly, where he readily 'confessed' that his organisation, the Khmer Serei, was funded and controlled by the CIA with the intention of overthrowing Sihanouk. Sihanouk asked the assembly to decide In's fate, and interpreted the response as a demand for the death penalty.

He was then handed over to a military tribunal, who sentenced him to death; "in his case, I had no inhibitions in signing the death warrant", commented Sihanouk. The Preap In affair was used by Sihanouk to underline his rejection of American aid from 1963.

In was born in Kampong Trach, Kampot, into a farming family, and was the nephew of In Tam, a provincial governor and prominent Cambodian politician of the post-independence years. In studied engineering in Phnom Penh; like Tam, he was a member of the Democratic Party, a broadly leftist, pro-independence party that was absorbed into Sihanouk's Sangkum movement in the later 1950s.

Preap In (Khmer: ព្រាប អ៊ិន, 1938–1964) was a Cambodian political dissident of the 1950s–1960s.