Causes of World War I corrective." British Diplomat Arthur Nicolson wrote in May 1914, “Since I have been at the Foreign Office I have not seen such calm waters.” 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, by two gun shots 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 assassination is significant because it was perceived by Austria-Hungary as an existential challenge
Trifko Grabež also hit by bomb shrapnel. Later that day, Gavrilo Princip managed to kill both Archduke Franz Ferdinand and his wife Sophie, Duchess of Hohenberg. Princip and Nedeljko Čabrinović were interrogated by the police. They kept to the promise to not tell anyone. Muhamed Mehmedbašić managed to escape to Serbia but Grabež, Popović and the Čubrilović's were arrested and charged with treason and murder after Danilo Ilić told the police. The police went round and investigated random people in order to identify potential accomplices. Once they spoke to Ilić, he lost his nerve and spilled the beans. All seven of the