Bosnian investigators detained four suspects for questioning over the attack on Serbian Prime Minister Alexander Vucic at the Srebrenica memorial earlier this month, Balkan Insight reports. Authorities released the suspects after questioning, though. Vucic was pelted with stones and slightly injured at the 20th anniversary commemoration of the Srebrenica massacre, which Vucic denies was an act of genocide. Tensions are again high between Serbia and Bosnia following the attack at the memorial.