The civil leadership of the resistance, represented by lawyer Sven Arntzen, demanded Quisling be treated like any other murder suspect and, on 9 May, Quisling and his ministers turned themselves in to police. Quisling was transferred to Cell 12 in Møllergata 19, the main police station in Oslo. The cell was equipped with a tiny table, a basin, and a hole in the wall for a toilet bucket. After ten weeks he was transferred to Akershus Fortress and awaited trial as part of the legal purge.
On 11 July, a further indictment was brought, adding a raft of new charges, including more murders, theft, embezzlement and, most worrying of all for Quisling, the charge of conspiring with Hitler over the 9 April occupation of Norway.
The trial opened on 20 August 1945. Quisling’s defense rested on downplaying his unity with Germany and stressing that he had fought for total independence, something that seemed completely contrary to the recollections of many Norwegians.
The prosecutor Annæus Schjødt called for the death penalty, using laws introduced by the government-in-exile in October 1941 and January 1942. The verdict was announced on 10 September, Quisling was convicted on all but a handful of minor charges and sentenced to death. Quisling was executed by firing squad at Akershus Fortress at 02:40 on 24 October 1945.