Kammala jumla mai zuwa: Da farko, kwaminisanci na Arewacin Vietnam ya kasance babban abokin haɗin gwiwa na Khmer Rouge yayin da yake yaƙi da Jamhuriyar Khmer ta Lon Nol a lokacin yakin basasa na 1970<unk>1975. Sai bayan da Khmer Rouge suka hau mulki ne al'amuran suka fara zama mai tsami, lokacin da a ranar 1 ga Mayu 1975 (ranar da ta gabata bayan da Khmer Rouge suka hau mulki)
Saigon ya fadi), sojojin Khmer Rouge sun mamaye tsibirin Phu Quoc da Tho Chau, inda suka kashe fararen hula fiye da ɗari biyar na Vietnamese; bayan harin, tsibiran sun sake dawowa da sauri ta hanyar Hanoi. Ko da a lokacin, halayen farko na Vietnamese sun kasance masu rikitarwa, kuma ya ɗauki Vietnam lokaci mai tsawo don amsawa da ƙarfi, domin abin da ya fara shi ne shirya al'amura "a cikin iyali".