Cambodia was divided into zones and special sectors by the RAK, the boundaries of which changed slightly over the years. Within these areas, the RAK's first task was the peremptory execution of former Khmer National Armed Forces (FANK) officers and of their families, without trial or fanfare to eliminate KR enemies. The RAK's next priority was to consolidate into a national army the separate forces that were operating more or less autonomously in the various zones. The Khmer Rouge units were commanded by zonal secretaries who were simultaneously party and military officers, some of whom were said to have manifested "warlord characteristics". Troops from one zone were frequently sent to another zone to enforce discipline. These efforts to discipline zonal secretaries and their dissident or ideologically impure cadres gave rise to the purges that were to decimate RAK ranks, to undermine the morale of the victorious army, and to generate the seeds of rebellion. In this way, the KR used the RAK to sustain and fuel its violent campaign. The Khmer Rouge was heavily influenced by Maoism, the French Communist Party and the writings of Karl Marx and Vladimir Lenin as well as ideas of Khmer racial superiority. Turning to look at the roots of the ideology which guided the KR intellectuals behind the revolution, it becomes evident that the roots of such radical thought can be traced to an education in France that started many of the top KR officials on the road to thinking that communism demanded violence. Influences from the French Revolution led many who studied in Paris to believe that Marxist political theory that was based on class struggle could be applied to the national cause in Cambodia. The premise of class struggle sowed the ideological seeds for violence and made violence appear all the more necessary for the revolution to succeed. In addition, because many of the top KR officials such as Pol Pot, Khieu Samphan and Kang Kek Iew (also known as Duch) were educators and intellectuals, they were being unable to connect with the masses and were alienated upon their return to Cambodia, further fuelling their radical thought. However, it is important to note that Vickery downplays the importance of personalities in explaining the DK phenomenon, noting that DK leaders were never considered evil by prewar contemporaries. Nonetheless, this view is challenged by some including Rithy Phan, who after interviewing Duch, the head of Tuol Sleng, seems to suggest that Duch was a fearsome individual who preyed on and seized upon the weaknesses of others.