After the Khmer Rouge evacuated Phnom Penh, Mok was the only senior government figure left in the city, tasked with overseeing its defence. Nuon Chear ordered the cadres in control of S-21 to kill all remaining inmates prior to it being captured by the Vietnamese. However, the troops guarding the city were unaware how close the Vietnamese Army actually were; the government had concealed the extent of the Vietnamese gains from the population. As the Vietnamese approached, many officers and other soldiers guarding the city fled; the defence was highly disorganised. There were isolated examples of Cambodian villagers killing Khmer Rouge officials in revenge. In January, Vietnam installed a new government under Samrin, composed of Khmer Rouge who had fled to Vietnam to avoid the purges. The new government renamed Cambodia the "People's Republic of Kampuchea". Although many Cambodians had initially hailed the Vietnamese as saviours, over time resentment against the occupying force grew.