 Complete the following phrase:  Chetnik units engaged in mass murders and war crimes. In 1991, the Croatian town of Erdut was forcefully taken over by the SDG and JNA and annexed to the puppet state of Republic of Serbian Krajina. Croats and other non-Serbs were either expelled or killed with Serbs repopulating empty villages in the area. On 1 April 1992, the SDG attacked Bijeljina and carried out a massacre of Muslim civilians. On 4 April, Chetnik irregulars helped the JNA in 