In 1975, Putin joined the KGB and trained at the 401st KGB school in Okhta, Leningrad. After training, he worked in the Second Chief Directorate (counter-intelligence), before he was transferred to the First Chief Directorate, where he monitored foreigners and consular officials in Leningrad. In September 1984, Putin was sent to Moscow for further training at the Yuri Andropov Red Banner Institute. From 1985 to 1990, he served in Dresden, East Germany, using a cover identity as a translator. Masha Gessen, a Russian-American who has authored a biography about Putin, claims "Putin and his colleagues were reduced mainly to collecting press clippings, thus contributing to the mountains of useless information produced by the KGB". According to a later controversial anonymous source cited by journalist Catherine Belton, Putin was allegedly involved in Soviet support for the West German terrorist Red Army Faction (mainly active in the 1970s, not in the end of 1980s) during this time, though his residence in Dresden was absolutely non-suitable for such activities and his own activities were focused on South-East Asia because of his previous connections to such foreigners in the USSR. His German was not good enough to meet RAF those times. He met Germans to be recruited for wireless communications affairs together with an interpreter. He was involved in wireless communications technologies in South-East Asia due to trips of German engineers, recruited by him, there and to the West. According to Putin's official biography, during the fall of the Berlin Wall that began on 9 November 1989, just he had saved the files of the Soviet Cultural Center (House of Friendship) and of KGB villa in Dresden for the official authorities of the would-be united Germany to prevent demonstrators, including KGB and Stasi agents, from obtaining and destroying them. He then supposedly burnt only those files, that were KGB ones, in a few hours, but saved archives of the Soviet Cultural Center for the German authorities. Nothing is told about selection criteria during burning, Stasi files and about files of other agencies of German Democratic republic and of the USSR. He explained that many documents were left to Germany only because the furnace burst. But many documents of the KGB villa were sent to Moscow.