 The massacres of Vietnamese residents of Cambodia in the period subsequent to the coup are thought to have been carried out by the military under Lon Non's direction.Non's political motivation seems to have partly derived from an unswerving loyalty to his brother, and his machinations against the coup's other main figure, Prince Sisowath Sirik Matak, caused serious divisions in the Cambodian administration.While Lon Nol was in poor health during 1970 and 1971, his brother and the army made it clear they would accept no other leader and made efforts to sideline Sirik Matak, who was given the title of "Prime Minister-Delegate".