Bjarne Thorsen Bjarne Winter Thorsen ( 9 January 1922 – 15 February 2001 ) was a Norwegian resistance member during World War II and later a naval officer . World War II . When World War II reached Norway on 9 April 1940 , with the German invasion , Thorsen was a student in secondary school . As early as 1940 , he got together with friends and decided to take up resistance work . The group was self - initiated , but they lacked contacts , knowledge and materials to actually conduct intelligence work . Two of them were sent to the United Kingdom : Bjarne Thorsen and Leif Utne . Utne travelled via Sweden , while Thorsen crossed the Norwegian Sea on the vessel " Duen " . After five weeks of training in radio , telegraphy , and secret codes , he returned to Norway with a transmitter . He landed on Sotra and went from there to Bergen . The radio communication post " Theta " was established on 4 December 1941 , with its headquarters at the famous seaside location Bryggen . The radio was operated out of a secret room in a house owned by the Dahm family ; Jan Dahm came to be the main operator . Thorsen returned to England when " Theta " was up and running . He had to return in early 1942 with new radio gear to make tracking by German intelligence harder . In total , he crossed the Norwegian Sea six times during this period . Among other things , " Theta " identified the presence of the German battleship " Tirpitz " in Norwegian waters , a highly important contribution to the Battle of the Atlantic . " Tirpitz " was located near Trondheim , far from Bergen , but " Theta " got the information from a scout travelling with the Hurtigruten . The message was sent on 17 January 1942 , and spurred a series of Royal Air Force attacks on the battleship . " Theta " later sent information about the German cruiser " Prinz Eugen " . Kristian Ottosen was also a member of the group running " Theta " , as was Helmer Dahl . After a request from Edward Victor Appleton , Thorsen helped Dahl and his family flee to the United Kingdom in April 1942 on the vessel " Borghild " . The Abwehr quickly became suspicious of " Theta " and tried to pinpoint its exact location . They managed to interfere with a transmission , attempting to trick the resistance members with a fake message . German authorities finally unveiled " Theta " in October 1942 , while conducting a razzia towards Bryggen , but most of the members managed to flee . Kristian Ottosen had already been captured , imprisoned , and tortured for information . Another member died in German captivity , while a third group member died elsewhere as a pilot . Thorsen continued his Allied war service as a telegrapher , and also attended the Norwegian Naval Academy . He was decorated with the St . Olav ' s Medal With Oak Branch , reportedly as the youngest Norwegian . He also received the King ' s Medal for Courage . Later career . After the war , Thorsen served in the Royal Norwegian Navy . He reached the rank of commander . He also spent some time working for the Governor of Svalbard . From the 1980s , he was a part of a project group aiming to register imprisoned Norwegian war sailors . In 1990 , he published the book " Usynlige soldater " , about the Secret Intelligence Service agents of Norway , together with Bjørn Rørholt . It was considered as providing hitherto unknown information . Thorsen lived in Eiksmarka , and died in February 2001 .