Serbia's monarchs, at the time from the royal House of Obrenović that maintained close relations with Austria-Hungary, were content to reign within the borders set by the treaty.

After a fierce battle in the dark, the attackers captured General Lazar Petrović, head of the Palace Guard, and forced him to reveal[dubious – discuss] the hiding place of King Alexander I Obrenović and his wife Queen Draga.

"[18] In May 1911, the Black Hand, a secret society dedicated to creating a Greater Serbia through "terrorist action", was established by key members of the Narodna Odbrana including Dimitrijević and Tankosić.

[25]Franz Ferdinand was an advocate of increased federalism and widely believed to favor trialism, under which Austria-Hungary would be reorganized by combining the Slavic lands within the Austro-Hungarian empire into a third crown.

Popović alleged that he sent Danilo Ilić to Belgrade to discuss this matter with Chief of Serbian Military Intelligence Colonel Dragutin Dimitrijević, known more commonly as Apis.

[43] At the time the two young Bosnian Serbs were in Belgrade eager to return to Austrian-occupied Bosnia to commit an attack on an imperial official, what they saw as performing the ultimate act of heroism.

[48] The three assassins from Belgrade testified that Major Tankosić, directly and through Ciganović, not only provided six hand grenades and four new Browning FN Model 1910 automatic pistols with .380 ACP ammunition,[47] but also money,[48] suicide pills,[49] training,[50] a special map with the location of gendarmes marked,[51] knowledge of contacts on a clandestine "tunnel" used to infiltrate agents and arms into Austria-Hungary,[52] and a small card authorizing the use of that tunnel.

[54] Princip, Grabež, and Čabrinović left Belgrade by boat on 28 May and traveled along the Sava river to Šabac where they handed the small card to Captain Popović of the Serbian Border Guard.

Popović, in turn, provided them with a letter to Serbian Captain Prvanović, and filled out a form with the names of three customs officials whose identities they could assume and thereby receive discounted train tickets for the ride to Loznica, a small border town.

Pašić's handwritten notes from the briefing (estimated by Dedijer to have taken place on 5 June) included the nickname of one of the assassins ("Trifko" Grabež) and also the name of Major Tankosić.

The local military commander, General Michael von Appel, proposed that troops line the intended route but was told that this would offend the loyal citizenry.

[83] In order to ensure the safety of the couple, General Oskar Potiorek decided that the imperial motorcade should travel straight along the Appel Quay to the Sarajevo Hospital so that they could avoid the crowded city center.

[89] According to the historian Joachim Remak, the reason for this is that Potiorek's aide Erik von Merizzi [de] was in the hospital, and was therefore unable to give Lojka the information about the change in plans and the driving route.

[90] The Sarajevo Chief of Police Edmund Gerde, who had earlier repeatedly warned Potiorek of insufficient security precautions for the imperial visit, was asked by one of the Archduke's aides to tell the drivers of the new route, but in the confusion and tensions of the moment, he neglected to do so.

[95] The assassin stepped up to the footboard of the car, and shot Franz Ferdinand and Sophie at point-blank range[94] using a Belgian-made Fabrique Nationale model 1910 .380 caliber pistol.

[108] He later resurfaced in Serbia where he joined Major Tankosić's Chetnik detachment during the war,[109] in 1916 the Serbian government imprisoned him on fabricated charges of treason during the Salonika trial, he was released in 1919.

[117] Following the assassination, Franz Joseph's daughter, Marie Valerie, noted that her father expressed his greater confidence in the new heir presumptive, his grandnephew Archduke Charles.

[134] Amongst those tried, four of the defendants had confessed their roles in Sarajevo and their final sentences were as follows:[135] In justifying the executions, Prime Minister Pašić wrote to his envoy in London: "...Dimitrijević (Apis) besides everything else admitted he had ordered Franz Ferdinand to be killed.

According to Serbian Military Attaché to Vienna, Colonel Lešjanin, Ambassador Jovanović, spoke to Biliński and "...stressed in general terms the risks the Archduke heir apparent [sic] might run from the inflamed public opinion in Bosnia and Serbia.

In 1924, J. Jovanović went public stating that his warning had been made on his own initiative, and what he said was that "Among the Serb youths (in the army) there may be one who will put a ball-cartridge in his rifle or revolver in place of a blank cartridge and he may fire it, the bullet might strike the man giving provocation (Franz Ferdinand).

[146] Biliński did not speak openly on the subject, but his press department chief confirmed that a meeting had taken place including a vague warning, but there was no mention of an ethnic Serb Austro-Hungarian soldier shooting Franz Ferdinand.

By choosing a military loyalist to convey the message, and by not including any of the specifics such as the conspirators' names and weapons, Pašić, a survivor, hedged his bets against the various possible outcomes and consequences of the impending assassination.

[153] After Serbia's victory over Bulgaria in Macedonia in the Balkan Wars, the "Black Hand" became moribund because of the death of its president and the failure to replace him, an inactive secretary, casualties, broken links between its three-man cells, and a drying up of funding.

[39] Serbian Military Intelligence – through remnants of the "Black Hand" – penetrated the Narodna Odbrana, using its clandestine tunnel to smuggle the assassins and their weapons from Belgrade to Sarajevo.

Apis's confession to ordering the assassination of Franz Ferdinand states that Russian Military Attaché Viktor Artamonov promised Russia's protection from Austria-Hungary if Serbia would ever come under attack.

[168]In August 1914, The Independent described the assassination as a "deplorable but relatively insignificant" reason for which[170] the financial system of the world is in chaos, that international commerce is suspended, that industries are everywhere demoralized and families ruined, and that millions of men in Europe have taken up arms with the intent to slaughter each other.

[172] After conducting a criminal investigation, verifying that Germany would honor its military alliance, and persuading the sceptical Hungarian prime minister Count István Tisza, Austria-Hungary issued a formal letter to the government of Serbia on 23 July 1914.

The letter reminded Serbia of its commitment to respect the Great Powers' decision regarding Bosnia and Herzegovina, and to maintain good neighborly relations with Austria-Hungary.

[189] Princip's weapon, along with the car in which the Archduke was riding, his bloodstained uniform and the chaise longue on which he died, are on permanent display in the Heeresgeschichtliches Museum in Vienna, Austria.

The bronze medallion of Ferdinand and Sophie, which was part of a monument that was erected on the site of the assassination and demolished in 1918 during Yugoslav rule, is currently preserved in the National Gallery of Bosnia and Herzegovina in Sarajevo.