The military reacted by portraying the party and its supporters as an atheist force of evil which had to be annihilated. The resulting carnage was deliberate, systematic, and spanned the country, with the most horrific and intense violence in Central and East Java, Bali, and northern Sumatra.
杀戮开始于1965年10月一场失败的政变之后。据称这场政变由印尼共策划。军方将印尼共及其支持者描述为邪恶的无神论势力，必须清剿。随后的大屠杀是一次有预谋、成系统、遍及全国，其中爪哇中部和东部、巴厘和苏门答腊北部的暴力最恐怖、最严重。