Around August 1991, Babić became a party to what war crimes prosecutors would later describe as a "joint criminal enterprise" to permanently forcibly remove the non-Serb population of the territory under his control, with the ultimate goal of making the region part of a new Serb-dominated state. According to prosecutors, his chief accomplices included Slobodan Milošević, other Krajina Serb figures such as Milan Martić, the Serb paramilitary leader Vojislav Šešelj, and Yugoslav Army commanders including General Ratko Mladić, at the time the commander of JNA forces in Croatia. All of them were indicted for war crimes, and some have been convicted. According to Babić's testimony during his war crimes trial, during the summer of 1991 the Serbian secret police – under Milošević's command – set up "a parallel structure of state security and the police of Krajina and units commanded by the state security of Serbia". A full-scale war was launched in which a large area of territory, amounting to a third of Croatia, was seized and the non-Serb population was either massacred or ethnically cleansed. The bulk of the fighting occurred between August and December 1991. Thousands more died and were deported in fighting in eastern Slavonia, but the JNA was the principal actor in that part of the conflict.