Early years Aarne Kauhanen's parents were the merchants Antti Kauhanen and Alma Sundsten. Kauhanen attended seven classes at the Finnish Normal Lyceum in Helsinki, and continued at the Finnish Business School, where he received his diploma in 1928. Kauhanen initially worked as an office clerk in Helsinki until he became an EK clerk in 1933. Kauhanen, known by the code name “Kuha”, was one of ValPo's most anti-Jewish employees.
Wartime During the Winter War, he was transferred to supervise foreign volunteers stationed in Ostrobothnia. Shortly after, he became the closest assistant to
Arno Anthoni, who was appointed head of Valpo in March 1941. Like Kauhanen, Anthoni was pro-Nazi and antisemitic, as was
Toivo Horelli, the interior minister who acted as their supervisor. After the outbreak of the
Continuation War, Kauhanen monitored the foreigners taken into custody and the refugees in the country, also conducting their interrogations. Fluent in German, Kauhanen later acted as a liaison between Valpo and the
Kriegsorganisation Finnland of the German military intelligence department, making several trips to German-occupied Estonia and Latvia on Horelli's order. Kauhanen also participated in the recruitment for the Finnish SS Battalion as the office manager of Insinööritoimisto Ratas, a cover organization that recruited volunteers. In the summer of 1942, Kauhanen belonged to a group that hosted
Heinrich Himmler during his visit to Finland. In 1944, Kauhanen escorted 11 deportees to Tallinn, when a Czech man reportedly died during a voyage in unclear circumstances. ==After the war==