Nikolic, 48, was assistant commander for security and intelligence of the Bratunac brigade, one of the Bosnian Serb army units involved directly in the July 1995 offensive against the UN-declared Srebrenica "safe zone" in eastern Bosnia and Herzegovina (BiH), which had provided shelter to about 30,000 Bosnian Muslim refugees.
Nikolić, 48, je bio zamenik komandanta za bezbednost i obaveštajni rad Bratunačke brigade, jedne od jedinica vojske bosanskih Srba koja je u julu 1995. bila direktno umešana u napad na Srebrenicu, «zaštićenu zonu» UN-a u istočnom delu Bosne i Hecegovine (BiH), u kojoj je utočište potražilo oko 30.000 izbeglih bosanskih Muslimana.