Commandant of the fortress

After the fall of Hegra fortress he was detained as a prisoner of war until June, then was released and for some time worked as a clerk at Orkla Metall factory in Tamskhavne (near Trondheim). There he established communication with the Norwegian resistance. In 1942 he was forced to flee to Sweden because of his impending arrest. In 1943 Holterman moved to England, where he commanded the Norwegian Brigade in Scotland. In 1944 he returned to Sweden for organization of the Norwegian police force. In beginning of May 1945 he returned to his native Trondelag and headed the disarm German occupational troops.