At a 1959 conference, the movement's leadership established the Kampuchean Labour Party, based on the Marxist–Leninist model of democratic centralism. Sâr, Tou Samouth and Nuon Chea were part of a four-man General Affair Committee leading the party. Its existence was to be kept secret from non-members. The Kampuchean Labour Party's conference, held clandestinely from September to October 1960 in Phnom Penh, saw Samouth become party secretary and Nuon Chea his deputy, while Sâr took the third senior position and Ieng Sary the fourth.