How did Austria Hungary react to the murder of archduke?

The assassination of Archduke Franz Ferdinand of Austria on June 28, 1914, triggered a chain of events that led to the outbreak of World War I. The assassination was carried out by a Serbian nationalist named Gavrilo Princip, who was a member of the Black Hand, a secret society dedicated to the unification of all South Slavic peoples into a single state.

The assassination caused outrage and indignation throughout Austria-Hungary, and in particular among the Austro-Hungarian military and political establishment. The Austro-Hungarian government immediately began investigating the assassination and quickly concluded that the Serbian government was involved. The government issued an ultimatum to Serbia on July 23, 1914, demanding that Serbia punish those responsible for the assassination, suppress anti-Austro-Hungarian propaganda, and allow Austro-Hungarian police officers to investigate the assassination on Serbian soil.

Serbia agreed to most of the demands, but rejected the one allowing Austro-Hungarian police officers to investigate on Serbian soil. Austria-Hungary declared war on Serbia on July 28, 1914, and thus began World War I.