He was accused of crimes against humanity and of violation of the laws and customs of war by the International Criminal Tribunal for the former Yugoslavia.

[6] Hadžić was involved in the Plitvice Lakes incident in late March 1991, beginning the Croatian War of Independence.

[12] On 25 June 1991, a group of eastern Slavonian Serbs organized a congress (Velika narodna skupština Slavonije Baranje i Zapadnog Srema) where they decided to constitute a "Serb Autonomous Oblast" (SAO) of the region, the SAO Eastern Slavonia, Baranja and Western Syrmia, and also to separate the region from the Republic of Croatia, which was still part of Yugoslavia.

[6] In September 1993, when Croatia started Operation Medak Pocket, Hadžić sent an urgent request to Belgrade for reinforcements, arms and equipment.

The request was ignored by the Serbian officials, although some 4,000 paramilitaries under the command of Arkan (Serb Volunteer Guard), arrived, to bolster the RSK army.

[13] After Operation Storm in August 1995, parts of RSK in eastern Slavonia remained outside the Croatian government's control.

Between 1996 and 1997, Hadžić was President of the Srem-Baranja district, after which the region was peacefully reintegrated into Croatia under the provisions of the Erdut Agreement.

In 2000, he attended the funeral of indicted war criminal Željko Ražnatović-Arkan in Belgrade, calling him a "big hero".

[18] Nenad Čanak, the leader of the League of Social Democrats of Vojvodina, claimed in 2006 that Hadžić was hiding in a monastery somewhere on Fruška mountain.

In October 2007, the Serbian government council for national security had offered €250,000 for information leading to Hadžić's arrest.

[23] Serbian police raided Hadžić's home on 9 October 2009 and impounded some of his belongings but did not make any statements following the operation.

[28] Police located him near the village of Krušedol on the slopes of Fruška Gora at 20:24,[29] where he was presumed to have been since he went into hiding following the ICTY indictment.

[34] With the arrest, one of the obstacles to Serbia's entry into the EU was removed,[27][35] and the country thus, according to the New York Times, "completed its obligations to the United Nations tribunal".

"[38] On 22 July, Justice Minister Snežana Malović announced that he had been extradited to the Hague in a small Cessna plane after being allowed visits by his sick mother,[39] wife, son and sister[40] in a convoy of jeeps and police cars that left the detention unit of the Serbian war crimes court in the morning and headed first to Novi Sad and then to Belgrade Nikola Tesla Airport.

The government of Croatia was said to have wanted to ensure that Hadžić serve the two prison sentences previously ordered in absentia by Croatian courts.

The prosecution completed its case in November 2013, and in February 2014 the tribunal rejected Hadžić's mid-trial motion for acquittal.