On 10 October 1942, Mladen Lorković, Croatian minister of foreign affairs, wrote a letter and memorandum concerning the increase in Chetnik anti-Croatian activity and terror that occurred between August and September, especially in Herzegovina, central Dalmatia, and Lika.
On 16 December 1942, Adolf Hitler ordered the Armed Forces Commander in South-East Europe, Generaloberst Alexander Löhr to crush the resistance in Yugoslavia and on 8 January 1943, Roatta and Löhr met in Zagreb where they devised a detailed plan for Case White.