After one failed attempt, Mehmedbašić was recruited by Danilo Ilić to join the plot to assassinate Archduke Franz Ferdinand of Austria. General Oskar Potiorek, Governor of the Austrian provinces of Bosnia and Herzegovina, was waiting to take the royal party to the City Hall for the official reception. Six assassins lined the route.
They were spaced out along the Appel Quay, each one had been instructed to try and kill Franz Ferdinand when the royal car reached his position.
The first conspirator on the route to see the royal car was Muhammed Mehmedbašić. Standing by the Austro-Hungarian Bank, but Mehmedbašić did not take action.
Mehmedbašić later said that a policeman was standing behind him and he feared he would be arrested before he had a chance to throw his bomb. Princip and Nedeljko Čabrinović were captured and interrogated by the police.
They eventually gave the names of their fellow conspirators.
Mehmedbašić managed to escape to Montenegro but Danilo Ilić, Veljko Čubrilović, Vaso Čubrilović, Cvjetko Popović and Miško Jovanović were arrested and charged with treason and murder. On 12 July, Mehmedbašić was apprehended by the Montenegrin authorities. However, before he was extradited he escaped from his prison in Nikšić two days later.
The Habsburg authorities suspected Montenegrin collusion in his escape and arrested the gendarmes who guarded Mehmedbašić.
During his captivity Mehmedbašić admitted his complicity in the assassination of Ferdinand. After the First World War Mehmedbašić returned to Sarajevo and in 1919 was pardoned for his role in the assassination.
Muhamed Mehmedbašić was killed by the Ustaše on 29 May 1943, during the Second World War.