Pavelić in Milan in early October, he travelled to London. He was arrested there after the Ustaše assassination of the Yugoslav King Alexander I in Marseilles, France. After his arrest he was handed over to French authorities, and spent three months in a Paris prison. In January 1935 he was extradited to Yugoslavia, and after 16 months spent in prison in Belgrade, he was acquitted by the Court for the Protection of the State. He was released on 16 April 1936, and briefly returned to Gospić before travelling to Austria in May. He later went to Germany, where he was involved in spreading Ustaše propaganda. In early 1937 he was living in Berlin when he was interrogated by the Gestapo, and under threat of arrest, he fled to France. This was followed by a stint in Budapest after which he returned to Berlin. By the late 1930s, the Ustaše had adopted the fascist principles of their financial backer and protector, Italy. Independent State of Croatia In late March 1941, Yugoslavia joined the Axis, but two days later, a pro-Allied coup d'état overthrew the government that had signed the treaty. In response, Adolf Hitler decided to invade and dismember Yugoslavia. The German-led Axis invasion of Yugoslavia in early April comprehensively defeated the Yugoslav military, and the country was divided up between the Axis powers. Before the Yugoslav government had capitulated, the Germans engineered the creation of the Independent State of Croatia, and placed Pavelić and the Ustaše in charge. Slavko Kvaternik, the most senior Ustaše still in Yugoslavia, proclaimed the Independent State of Croatia on 10 April 1941, and Artuković and the other émigré Ustaše returned to Zagreb. On 12 April, Kvaternik formed an interim government, which included Artuković. Pavelić arrived in Zagreb on 15 April, and on the following day, Artuković became the Interior Minister in the first Croatian government. As a member of Pavelić's trusted inner circle, Artuković carried out the orders he was given. On 17 April, to provide authority for Ustaše policies targeting Serbs, Jews, Roma and anti-Ustaše Croats and Bosniaks within the NDH, Pavelić proclaimed the Law Decree on the Defence of the People and the State. It prohibited any person from acting against the Croatian people and its interests, for which the penalty was death. Such alleged offences were to be dealt with in a summary manner by a panel similar to a court martial.