Nikola Pasic, the prime minister of Serbia, Pasic heard about the plot and gave instructions for the three men to be arrested. However, his orders were not implemented and the three man arrived in Bosnia-Herzegovina where they joined forces with fellow conspirators, Danilo Ilic, Vaso Cubrilovic, Cvijetko Popovic, Misko Jovanovic and Veljko Cubrilovic.
On Sunday, 28th June, 1914, Franz Ferdinand and Sophie von Chotkovato were assassinated by Gavrilo Princip. Princip and Nedjelko Cabrinovic were captured and interrogated by the police. They eventually gave the names of their fellow conspirators. Muhamed Mehmedbasic managed to escape to Serbia but Popovic, Danilo Ilic, Vaso Cubrilovic, Veljko Cubrilovic and Misko Jovanovic were arrested and charged with treason and murder.
All the men were found guilty. Under Austro-Hungarian law, an offender under twenty could not be executed. Nedjelko Cabrinovic, Gavrilo Princip and Trifko Grabez therefore received the maximum penalty of twenty years, whereas Vaso Cubrilovic got 16 years and Popovic 13 years.