The Article is devoted to the problem poorly developed in the domestic and Finnish historiography - the participation of the Finnish special services in the Civil war in Karelia in 1918 - 1922. Since 1918, the moment of independence, the Finnish leadership had aggressive plans to join the Eastern (Russian) Karelia to the Finnish state. Finland under the pretext of helping a “fellow” - Ingrian, Karelians and Veps in Eastern Karelia in 1918 - 1922, almost led an undeclared war against Soviet Russia. In this war the most active part was taken by representatives of both special services of Finland: military intelligence at the General staff of Defensive forces of Finland and the Central detective police (VALPO). The article highlights the activities of famous Finnish agents - Paavo Marttina, Gustav Rosenström and others. During the so-called “tribal wars” of 1918-1922, they not only carried out active reconnaissance and sabotage work, but also carried out the recruitment of agents among the local Karelian population. Many of the individuals they recruited then became experienced agents themselves. So, one of the prominent leaders of the Suojärvi razvedrota Finnish military intelligence was Matthew Buldaev (later changed the name to Matti Poimela), recruited by Finnish intelligence during the campaign of the Finns in Olonets Karelia in 1919 Some of the agents recruited during the Civil war in Karelia, in turn, in the 1920s-1930s, headed various units of the Finnish special services and took an active part in the Soviet-Finnish war of 1939-1940, as well as in the fighting of Finland against the USSR in 1941-1944.