Serbian authorities say that ex-Yugoslav army major Simo Dubajic who is suspected by Croatia of mass post-World War II executions has died, AP reported. Interior Ministry spokeswoman Suzana Vasiljevic said Saturday that 86-year-old Dubajic had died of natural causes earlier this week. Dubajic is suspected in Croatia of ordering the 1945 executions of around 13,000 Croatian pro-Nazi soldiers and civilians. The investigation was Croatia's first into the post-WWII killings by antifascists.