[3] Although he was problematic in his early teens, he finished an auto mechanic program and medicine school in Belgrade.

[citation needed] He joined the Serb Volunteer Guard in 1992 under the control of Serbian warlord Arkan.

[5] In 1996, following the dissolution of the Serb Volunteer Guard, on the request by head of the State Security Directorate Jovica Stanišić, Ulemek joined the re-structured Special Operations Unit.

In 1999, Ulemek became the leader of the "Red Berets",[6] and became the official commander of "JSO SDB Serbia" in April 2001.

On 12 March 2003, right after the assassination of Serbian Prime Minister Zoran Đinđić, a country-wide manhunt, named Operation Sabre, was initiated.

Ulemek claimed that he had been hiding in his house the entire time, which made lot of controversy in public.

In verdict by Special Court for Organized Crime in Belgrade Presiding Judge Nata Mesarović, Đinđić's assassination was described as "a political murder, a criminal act aimed against the state", in which police officers and the mafia had joined hands to kill Đinđić and gain political power.