Part 1

Slobodan Praljak, with three university degrees in engineering, sociology, and theater, had been a freelance artist, theater director and Television and movie director in socialist Yugoslavia. Once the Yugoslav war broke in 1991 he joined the Croatian Army and by 1992 had become a major general in said army. He also served as Assistant Minister of Defence for the Republic of Croatia under minister of defense Gojko Susak and a member of the Crotian Defense Council (Hrvatsko vijeće obrane, HVO), the armed forces of Herceg-Bosna. Crucially this position as the the senior representative of the Croatian Ministry of Defense to the Herceg-Bosna government and HVO forces – what this was I'll explain shortly – was what lead to his indictment in The Hague.

So, for some context here: Herceg-Bosna was an internationally not recognized proto-state during the Yugoslav wars, proclaimed by the HDZ in Bosnia, an offshoot of Franjo Tuđman's ruling party in Croatia in 1991. As you might be aware, the background to this was the Yugoslav wars initially breaking out over Slovenia and Croatia declaring their independence from socialist Yugoslavia after elections had been held and they had been guaranteed international recognition. The Yugoslav state as well as the Republic of Serbia tried to prevent this secession by occupying these territories militarily and while the war with Slovenia was over in 10 days, the one with Croatia went on longer, in part because many Serbs in Croatia did not favor becoming part of a new Croat state.

With the throws of the break-up of Yugoslavia, despite the various Republics having fixed borders from their time in the Yugoslav Socialist Federation, saw a chance to unite "their people" under their rule and create ethnically homogeneous nation states. Determining who "their people" were was an often difficult task – I go into this in this answer – and exacerbated tensions within the new state of Croatia between those who understood themselves as Serbs and those who understood themselves as Croats. But it even more so lead for people like Tuđman and also Milosevic to the question what would happen with Bosnia.

Historically – at least as far back as is relevant to this answer – Bosnia was an administrative territory of the Ottoman Empire that following the Berlin conference in 1878 had come under Austrian-Hungarian control. Since back then it was a territory that was comprised of several different regions and of Croats, Serbs, and Bosniaks (muslim Bosnians – again referring to the difficulty discussed in the above linked answer). After WWI it became part of the Yugoslav Kingdom and was organized in several new administrative units, However, after WWII it was reconstituted as the Socialist Republic of Bosnia and Herzegovina. Because the territory of BiH was divided into several areas with different majority populations (Serbs, Croats and Bosnians) in the nationalist fervor of the Yugoslav wars, both Serbia and Croatia saw a chance to via military means "unite" their people by cutting out chunks of Bosnian territory that had their respective majority populations. In the case of the Serbs this was the famous Republika Srpska as declared in 1992 by, among others, Radovan Karadžić and Ratko Mladić. In the case of Croatia, it was the Republic of Herceg-Bosna, that was slated to eventually end up part of the Croatian state, and which was centered in the Herzegovin and had its capital in Mostar.

Initially – and in line with the thinking that Bosniaks were but Croatians of Muslim faith – both Herceg-Bosna as well as the new Republic of Croatia cooperated with both local Muslims and the government of Bosnia under Alija Izetbegović but tensions already existed and once the Supreme Court of the Republic of Bosnia declared Herceg-Bosna to be an illegal entity in 1993, and what was called the Croat–Bosniak War – a war within a war so to speak since both Croatia and Bosnia were busy at the same time fighting Yugoslav and Serb-Montenegron forces and irregulars – escalated.

Within this conflict, the HVO as the military of the Republic of Herceg-Bosna would play a particular unsavory role and this is where we return to Praljak. As the ICTY's indictment of Praljak and others states

In his various positions and functions, SLOBODAN PRALJAK exercised de jure and/or de facto command and control over the Herceg-Bosna/HVO armed forces. At times relevant to the indictment, he exercised effective control and substantial influence over the Herceg-Bosna/HVO armed forces (including the operative zone commanders). He was responsible for the management, organization, planning, preparation, training, discipline, supply, deployment and operations of the Herceg-Bosna/HVO armed forces. He issued organisational, strategic and combat orders. It was part of his responsibility to ensure that all Herceg-Bosna/HVO forces conduct themselves in accordance with the Geneva Conventions and international humanitarian law and that all prisoners, detainees and other persons held by Herceg-Bosna/HVO forces be treated in compliance with such conventions and law. SLOBODAN PRALJAK also had command authority over the Herceg-Bosna/HVO civilian police, when they acted under or in co-ordination with the Herceg-Bosna/HVO armed forces during times of armed conflict. He was closely involved in all aspects of Herceg-Bosna/HVO military planning and operations.

And when the HVO committed war crimes, it was therefore understood that Praljak was at least in part responsible.

Under his command, HVO forces committed murders against the Muslim civilian Muslim population, carried out ethnic cleansing, destroyed property, committed sexual assault, and forced civilians into forced labor. In his case especially pertinent was the case of the Prozor municipality. 62% of the municipality's inhabitants declared themselves Croat in the 1991 census and 36.5% declared themselves Muslim but the principal town, the town of Prozor, was majority Muslim with approx. 60%. Herceg-Bosna initially claimed Prozor as part of their territory but tensions were high and escalated in October 1992. HVO forces attacked Prozor and took the town from the Armed Forces of Bosnia and Herzegovina (ABiH) that had held the town up until that point. After taking Prozor, HVO troops destroyed property, imprisoned Muslims in the local school and mistreated them, either detained or forced Muslims to flee and committed murders against he Muslim population both in the town of Prozor and surrounding villages. Citing an incident from the indictment:

On or about 31 July 1993, Herceg-Bosna/HVO forces took approximately fifty Muslim detainees from the Secondary School Centre to the confrontation line at Makljen Crni Vrh. The Herceg-Bosna/HVO forces tied the detainees together with telephone cable around their arms and necks and forced them to walk in front of HVO soldiers in the direction of ABiH positions near the forest. While the detainees were walking in front of the HVO soldiers, the HVO soldiers opened fire in their direction and at least twenty detainees were killed. The dead detainees were untied and left behind while the HVO forced the remaining detainees to walk toward the forest.

Prlajak was found not only to have known about this but to have violated his responsibilities to international law by not having stopped it and by encouraging such actions further. When the HVO area commander reported in 1992 that Prozor town was "ethnically pure" to Praljak and others, this was met with approval going to show that the campaign of mistreatment and ethnic cleansing was encouraged from above.

Praljak further ordered HVO forces in the Vares municipality to "show no mercy", which lead to mass arrests in the area as well as the attack on the village of Stupni Do during which HVO forces robbed the population of valuables, sexually assaulted women and killed at least thirty-one men and six women and children as well as destroyed almost the entire village.

Furthermore, the HVO and Praljak took command of the Dretelj camp, a prison and detention facility they used to imprison Muslims. Dretelj had originally been founded by the Hrvatske obrambene snage, HOS, the military of the Croatian Party of Rights, a right-wing nationalist party. HOS via the symbols it used as well as by the use of that particular name, which translates to "Croatian Defense Forces" took direct inspiration from WWII fascist Ustasha. However, HOS was dissolved in 1992/3 and integrated into HVO after the Tuđman government allegedly ordered the assassination of its leader Blaž Kraljević.

With the integration of HOS into HVO came also control of the Dretelj camp where they detained at least 2,270 Bosniak men. Conditions in the camp were horrible with bad ventilation, bad food, overcrowding and physical maltreatment. At least four detainees died and several guards were later convicted in a variety of courts for torturing prisoners. Praljak was one of the people ultimately responsible for this camp, knew about these conditions and yet made no effort to improve on them and let them go on like they were.