On 4 July 1950 North Korean People’s Army came in Incheon. But the mayor of Incheon city escaped on June 28 when the army didn’t yet enter into Incheon, and civil servants, military and police of Incheon also pulled out. By the way, on June 29 the military and police came back by guidance of right-wing youth organization and raided and killed more than 700 ‘civilians’ who was ready to welcome North Korean People’s Army at the Incheon City Hall. Many of dead were Members of Federation Protecting and Guiding the Public of Incheon and their family. After occupation of Incheon, North Korean People’s Army received major agencies and reformed the organizations. Occupation force brought more than half of people needed to rule occupied area over from North Korea. More than half of 99 members in police of Incheon were from North Korea and most of them were the Korean Workers’ Party members, who controled center of police and served as chiefs of affiliated organizations. Most of local people chosen and appointed were from poor peasant and labor and helped their seniors from North Korea carry out missions to cooperate with the occupation rule and wartime mobilization. Massacre happened on the verge of occupation made it difficult for occupation force to obtain local assistants. Meanwhile, North Korean People’s Army paid attention to the fact that the hundreds of leftists and citizens were killed just before their capture and actively took advantage of the fact for their occupation rule. The funeral home for victims of the Federation Protecting and Guiding the Public reminded of the place to enlist volunteer army. Also propaganda and incitement reminding of sacrifices became a driving force to sustain their occupation rule. Because of the tragedy right before North Korean people’s army’s occupation and early escape of civil servants, while government authority before war lost popularity, North Korean people’s army seemed to control fully the community of Incheon. However continued bombing from the air and naval bombardment from the sea by the US army destroyed the daily lives of citizens and made fully captured rule impossible. Massacre of leftist weakened the base of their occupation rule, too. At last, sharply amid fears about large-scale landing of UN army, North Korean people’s army began to prepare the punishment of right-wing political prisoners which had been restraint before retreating.