Answer:
He was assassinated by Gavrilo Princip, a member of the secret society known as the Black Hand. it was on the 28th of June in Bosnia. he was killed because the people of Bosnia were fed up of being controlled by Austria-Hungary and wanted to be free. Gavrilo was part of a whole gang of people who lined the streets ready to kill. he thought somebody else had already done the job when a loud bang was heard and there was a whole load of commotion, but when the car came into view he was still alive. Gavrilo had no time to think and straight away jumped up and shot the gun, pulling the trigger to many times to count. Both the Archduke and his wife were dead. But Gavrilo was rained down upon with kicks and punches. It was all over...
hope that helps!