 In early February 1943 , during their advance north @-@ west into Herzegovina in preparation for their involvement in Case White , the combined Chetnik force killed large numbers of Muslims in the targeted areas . In a report to Mihailović dated 13 February 1943 , Đurišić wrote that his Chetniks had killed about 1 @,@ 200 Muslim combatants and about 8 @,@ 000 women , children and the elderly , and destroyed all property except livestock , grain and hay , which they seized . Đurišić reported that : 
