Frustrated with Chetnik and Partisan resistance they could engage and hurt in combat but never destroy, German commanders resorted to a policy of reprisals against civilian hostages. For every German soldier killed, one hundred Yugoslavs were to be slain. While for the most part ineffective, it would occasionally convince some Yugoslavs to engage local rather than German enemies in combat. Three important indigenous military forces came into existence almost as soon as the dust from the invasion had settled. The Serbian Chetniks, the Communist Partisans of Tito and the Croatian Ustashi would each carve their marks into Yugoslavian collective history.
The first to organize were the Chetniks. They were a force of Serbian irregulars loyal to King Peter and under the command of Colonel Drazha Mihailovich, a Serbian army officer who had escaped to the hills in traditional Balkan fashion to continue the war. His overall goal was the return of the Serbian King Peter at any cost. Seeing the communists of Tito as a threat to be feared as much as the occupiers, Mihailovich was not above occasional collaboration with the Germans and the Italians if it presented a chance to strike a blow against the Partisan forces. The Chetniks were involved in constant series of atrocities with the Croatian Ustashi involving tit for tat massacres often accompanied with torture and mutilation of the dead. Not limited to war upon Croatians, Partisans and the occupying forces, the Chetniks were also responsible for systematic killing of 9,200 Moslems in Bosnia-Herzegovina, sinking into frenzies of rape and torture of the local inhabitants. The anti-partisan policy of Mihailovich could only have one inevitable conclusion as the partisan continued to grow in strength. By the end of the war they had been all but destroyed and Colonel Mihailovich was captured, tried for collaboration with the Germans and the Italians and sentenced to death.
