Operation Labrador Operation Labrador was a false flag operation carried out by the Yugoslav Air Force branch of the Counterintelligence Service ( KOS ) in Croatian capital city of Zagreb during the early stages of the Croatian War of Independence . It was devised as a seres of terrorist attacks carried out in order to discredit Croatia , making it appear a pro - fascist state . Two attacks were carried out on 19 August 1991 — against the Jewish Community Centre and Jewish graves at the Mirogoj Cemetery . There were no casualties in the two bombings . Additional attacks targeted national railway network , and made to appear as if ordered by the Croatian President . Operation Labrador was complemented by Operation Opera — a propaganda campaign devised by the KOS to feed disinformation to media . Further activities of Operation Labrador were abandoned in September , after the Croatian authorities captured Yugoslav Air Force regional headquarters in Zagreb , and confiscated documents related to the operation . Since the authorities took nearly a month to interpret the captured documents , the principal agents involved in the bombings fled . Fifteen were arrested in connection with the attack , but they were released in a prisoner exchange . Five KOS agents involved in Operation Labrador were tried in FR Yugoslavia on terrorism charges and acquitted . Croatian authorities captured two KOS agents who were a part of the operation and tried them along with seven other agents who were tried " in absentia " . The agents who were in custody during the trial were acquitted , while the trials " in absentia " resulted in convictions . Existence of Operation Labrador was confirmed through testimony of a former KOS agent , Major Mustafa Čandić , during the Trial of Slobodan Milošević at the International Criminal Tribunal for the former Yugoslavia in 2002 . Background . In August 1990 , an insurrection took place in Croatia centred on the predominantly Serb - populated areas of the Dalmatian hinterland around the city of Knin , as well as in parts of the Lika , Kordun , and Banovina regions , and settlements in eastern Croatia with significant Serb populations . The areas were subsequently named SAO Krajina ( Serb Autonomous Oblast ) and , after declaring its intention to integrate with Serbia , the Government of Croatia declared it to be a rebellion . By March 1991 , the conflict escalated into the Croatian War of Independence . In June 1991 , Croatia declared its independence as Yugoslavia disintegrated . A three - month moratorium followed , after which the decision came into effect on 8 October . The SAO Krajina , renamed Republic of Serbian Krajina ( RSK ) on 19 December , then initiated a campaign of ethnic cleansing against Croatian civilians . As the Yugoslav People ' s Army ( JNA ) increasingly supported the SAO Krajina and the Croatian Police was unable to cope with the situation , the Croatian National Guard ( ZNG ) was formed in May 1991 . The development of the military of Croatia was hampered by a UN arms embargo introduced in September , while the military conflict in Croatia continued to escalate . The JNA maintained substantial forces in Croatian capital , Zagreb , throughout 1991 . Bombings . In August 1991 , Yugoslav Air Force branch of the Counterintelligence Service ( KOS ) executed a series of activities , codenamed Operation Labrador , aimed at discrediting Croatia . Operation Labrador was planned to consist of several terrorist attacks intended to complement activities of Operation Opera — a propaganda campaign devised to feed disinformation to media . The two operations put together were meant to portray Croatia as a pro - fascist state . An alternative name for Operation Opera was Operation Opera - Orijentalis , or Operation Opera Orientalis . Operation Labrador was headed by Colonel General Slobodan Rakočević , head of the Yugoslav Air Force branch of the KOS , based in Zemun . In Zagreb , operational control of Labrador was assigned to Lieutenant Colonel Ivan Sabolović , and Major Čedo Knežević . Lieutenant Colonel Radenko Radojčić was tasked with storage of a substantial quantity of explosives in Zagreb and its surrounding area , as well as planting of explosive devices . The explosives and some weapons were stored at several sites . On 19 August , Jewish Community Centre in Palmotićeva Street in Zagreb , and Jewish graves at the Mirogoj Cemetery , were bombed as a part of Operation Labrador . The explosions caused damage , but there were no casualties . There were no public claims of responsibility for the attack . Besides the two explosions in Zagreb , agents assigned to the Operation Labrador are considered to be responsible for bombing of the Zagreb – Belgrade railway near Vinkovci and a railway line between Glina and Vojnić . The railway attacks are alternatively associated with Operation Opera . Aftermath . In the immediate aftermath of the bombings in Zagreb , Josip Manolić , who had just been appointed head of the Croatian intelligence service , claimed the Croatian right - wing extremists were responsible . Operation Labrador was apparently abandoned after the ZNG and the Croatian police captured Yugoslav Air Force headquarters in Zagreb on 15 September , during the Battle of the Barracks . The materials captured inside the facility included codes and computer disks related to Operation Labrador , as well as Sabolović ' s notes . Sabolović turned the materials over to his immediate superior at the headquarters , Mirko Martić , but Martić failed to destroy them . In response , Sabolović fled Zagreb . Nonetheless , Croatian police took almost a month to interpret the captured materials properly and uncover Operation Labrador . Sabolović later claimed that only a part of Operation Labrador network was dismantled , but he was contradicted by KOS Major Mustafa Čandić who was posted at the Zemun headquarters of KOS . In the autumn of 1991 , Croatian intelligence services launched Operation Janissary ( " Operacija Janjičar " ) aimed at dismantling remaining KOS network in Croatia . The operation was a joint operation of all Croatian intelligence services . It was authorised by Ivan Vekić and Gojko Šušak , then interior and defence ministers , and initially headed by Josip Perković . Fifteen were arrested by the end of 1991 , and then exchanged for Anton Kikaš , who was captured by the JNA while smuggling a plane - load of weapons to Croatia . The operation also produced a list of suspected KOS operatives in Croatia containing 1 , 789 names and pseudonyms . Rakočević , Sabolović , Radojčić and two other former KOS agents were tried in Belgrade in 1993 . The five were charged with instigation to terrorism and other charges , but all were acquitted . Radojčić was arrested in Zagreb in late 1993 . The second Trial of Radojčić and eight other persons charged in connection with Operations Labrador and Opera , held in Zagreb , ended with acquittal of Radojčić and Ratomir Mažibrada , who were in custody , and convictions of seven remaining defendants tried " in absentia " . Testifying at the Trial of Slobodan Milošević at the International Criminal Tribunal for the former Yugoslavia in 2002 , Čandić stated that all Operation Labrador agents left Zagreb and took the remaining documents away with them . He also said that the KOS had an extensive network of informants within Croatian intelligence services and the ruling Croatian Democratic Union in 1991 . Čandić also testified that the railway bombing near Vinkovci was meant to be seen as if ordered by then Croatian President Franjo Tuđman . Bomb damage to the Jewish Community offices was repaired in February – September 1992 , using government funds .