[6][7] In March 2003, Serbian Prime Minister Zoran Đinđić was assassinated under the orders of Zemun Clan leader Milorad "Legija" Ulemek and Dusan Spasojevic.
On 23 May 2007 the Belgrade Special Court for Organised Crime found twelve men, including Kalinić, guilty of conspiring the murder of Serbian Prime Minister Zoran Đinđić.
On 18 January 2008, Kalinić was sentenced by the Serbian court in absentia to 40 years imprisonment for involvement in killings, kidnappings, terrorist acts, and the murder of Đinđić.
While recovering in the hospital, Kalinić offered cooperation to Croatian investigators, including testimony on the organization of the assassination of Đinđić, and the names of the people who ordered the murder of Zoran Vukojević, a protected witness.
[11] Sretko Kalinić was sentenced by a Serbian court following testimony from former members of the criminal Zemun Clan, Dejan Milenković and Saša Petrović.
[1][2][4][12] Miloš Simović and Sretko Kalinić accused each other of the murder of their associate, Cvetko Simić, whose body parts, except for his head, were found in a lake near Zagreb.