Ostojic and another two inhabitants of the Borovo settlement near the eastern city of Vukovar were nabbed by the police immediately after an incident of 20 October when the hand grenade hit the grass area in front of the offices of the Croatian Party of Rights (HSP). Two HSP activists sustained light injuries in the explosion.
The explosion ensued after a heated debate and an exchange of verbal insults between HSP members and the three inhabitants of ethnic Serb origin. The argument came to a head when those involved in the discussion began a fight. After a short scuffle, Ostojic and the two men accompanying him left the HSP club. Shortly after that, the explosion rocked the area.
The police, however, established that only Ostojic was responsible for the attack, and the two men in his company were released after being arrested. Ostojic refused to accept his responsibility.