Beginning in later October 1965, and feeding off pent-up communal hatreds, the Indonesian army and its civilian allies (especially Muslim vigilante groups) began to kill actual and suspected members and associates of the PKI. The US government covertly supported the massacres, providing extensive lists of suspected communists to be targeted. The killings started in the capital Jakarta, spread to Central and East Java, and later Bali. Although killings occurred across Indonesia, the worst were in PKI strongholds of Central Java, East Java, Bali, and northern Sumatra. The massacres reached their peak over the remainder of the year before subsiding in the early months of 1966. The estimates of the death toll of the violence range from over 100,000 to three million, but most scholars accept a figure of around 500,000. Many others were also imprisoned, and for the next ten years, people were still being imprisoned as suspects. It is thought that as many as 1.5m were imprisoned at one stage or another. As a result of the purge, one of Sukarno's three pillars of support, the PKI, had been effectively eliminated by the other two, the military and political Islam, helped in Bali by proponents of the Balinese caste system who saw the PKI and its allies as a threat to their way of life.