There were 6 assassins sent to kill Archduke Franz Ferdinand and 1 of them threw a bomb that exploded under the wrong car. His assassination failed, he took a cyanide pill and jumped into the river. The pill only induced vomiting and the river was only 13cm deep. He failed at killing himself too.
On 28 June 1914, Archduke Franz Ferdinand of Austria, heir presumptive to the Austro-Hungarian throne, and his wife, Sophie, Duchess of Hohenberg, were shot dead in Sarajevo by Gavrilo Princip, one of a group of six assassins (five Serbs and one Bosniak) coordinated by Danilo Ilić, a Bosnian Serb and a member of the Black Hand secret society. The political objective of the assassination was to break off Austria-Hungary’s South Slav provinces so they could be combined into a Yugoslavia. The assassins’ motives were consistent with the movement that later became known as Young Bosnia. The assassination led directly to the First World War when Austria-Hungary subsequently issued an ultimatum to the Kingdom of Serbia, which was partially rejected. Austria-Hungary then declared war.
On top of these Serbian military conspirators was Chief of Serbian Military Intelligence Dragutin Dimitrijević, his right-hand man Major Vojislav Tankosić, and the spy Rade Malobabić. Major Tankosić armed the assassins with bombs and pistols and trained them. The assassins were given access to the same clandestine network of safe-houses and agents that Rade Malobabić used for the infiltration of weapons and operatives into Austria-Hungary.
The assassins, the key members of the clandestine network, and the key Serbian military conspirators who were still alive were arrested, tried, convicted and punished. Those who were arrested in Bosnia were tried in Sarajevo in October 1914. The other conspirators were arrested and tried before a Serbian kangaroo court on the French-controlled Salonika Front in 1916–1917 on unrelated false charges; Serbia executed three of the top military conspirators. Much of what is known about the assassinations comes from these two trials and related records.
The motorcade passed the first assassin, Mehmedbašić. Danilo Ilić had placed him in front of the garden of the Mostar Cafe and armed him with a bomb. Mehmedbašić failed to act. Ilić placed Vaso Čubrilović next to Mehmedbašić, arming him with a pistol and a bomb. He too failed to act. Further along the route, Ilić placed Nedeljko Čabrinović on the opposite side of the street near theMiljacka River arming him with a bomb.
At 10:10 am, Franz Ferdinand’s car approached and Čabrinović threw his bomb. The bomb bounced off the folded back convertible cover into the street. The bomb’s timed detonator caused it to explode under the next car, putting that car out of action, leaving a 1-foot-diameter (0.30 m), 6.5-inch-deep (170 mm) crater, and wounding 16–20 people.
Čabrinović swallowed his cyanide pill and jumped into the Miljacka river. Čabrinović’s suicide attempt failed, as the cyanide only induced vomiting, and the Miljacka was only 13 cm deep due to the hot, dry summer. Police dragged Čabrinović out of the river, and he was severely beaten by the crowd before being taken into custody.
The procession sped away towards the Town Hall leaving the disabled car behind. Cvjetko Popović, Gavrilo Princip, and Trifun Grabež failed to act as the motorcade passed them at high speed.