After the capitulation of all German forces he was taken prisoner of war by the Red Army of the Soviet Union. He was sentenced to 25 years' imprisonment for war crime charges against the destruction of cities and art on 29 June 1950. According to the court, Foertsch permitted the destruction of cities of Pskow, Novgorod and Leningrad by his troops, and the destruction of historical art and memorials in Gatschina, Petergof, Pavlovsk and Pushkin.