Jurak collaborated on Mate Ujević 's '' Croatian Encyclopedia '' . In 1943 , Jurak was among those invited by the International Committee of the Red Cross to take part in an investigation into the massacre of ethnic Ukrainians at Vinnytsia in the 1930s . This investigation concluded that the Soviet Union had been responsible for the massacre . He also commented on the Soviet responsibility for the Katyn massacre . His article about it was published in the Zagreb newspaper run by the Independent State of Croatia . When World War II in Yugoslavia ended , OZNA had Jurak killed by firing squad in Zagreb in June 1945
Vinnytsia
Vinnytsia massacre
Ljudevit Jurak