Arne Treholt (13 December 1942 – 12 February 2023) was a Norwegian-born, Russia-based convicted felon and KGB agent who was convicted of treason and espionage on behalf of the Soviet Union against Norway during the Cold War and sentenced to 20 years in prison. Before his arrest in 1984, he was successively a journalist, a junior Norwegian Labour Party politician and a medium-level official of the Ministry of Foreign Affairs in Norway, while secretly working for the KGB. Treholt provided the Soviet Union with information on the Norwegian defense plans for northern Norway in the event of a Soviet invasion, material weaknesses in the Norwegian Armed Forces, mobilization plans, information on how to most effectively take out Norwegian soldiers, Norwegian emergency plans, the location of NATO allies' stored equipment in Norway, and the meeting minutes of the Prime Minister and Foreign Minister. Treholt was found to possess a secret bank account in Switzerland with a substantial illicit amount. Treholt's espionage is generally seen as the most serious spy case in the modern history of Norway. Following his arrest, Treholt was described as "the greatest traitor to Norway since Quisling". The Treholt case was the last major espionage case in Norway during the Cold War, following the earlier Haavik case, the Høystad case and the Sunde case. Treholt was arrested in 1984 and sentenced to 20 years in prison the following year, of which he served nine in a maximum security prison. His early release was granted in 1992 based on claimed ill health. After his release from prison Treholt moved to Russia, where he started a company together with a former KGB general. He always maintained that he had never provided his contacts with any information that could have endangered his country's security. In 2010, his case took a new twist when Geir Selvik Malthe-Sørenssen, who was later revealed to be a con artist and sentenced to prison himself, claimed that Arne Treholt had been the victim of a conspiracy. He applied for a review of his case, which was rejected a year later by the commission in charge of examining it. Treholt was occasionally active in public debate, and he was accused by Norwegian media of promoting Russian propaganda. Following the 2022 Russian invasion of Ukraine, Treholt and Russian propagandist Glenn Diesen wrote an article that claimed that Russia has "legitimate interests and security needs" and claimed that Russia