Active reserve (KGB) officers with a military rank who worked undercover in the Soviet Union. "Trusted contacts" were high placed civilians who collaborated with the KGB without signing any official working agreements, such as directors of personnel departments at various institutions, academics, deans, or writers and actors. Informers were citizens secretly recruited by the KGB, sometimes using forceful recruitment methods, such as blackmail. The precise number of people from various categories remains unknown, but one of the estimates was 11 million "informers" in the Soviet Union, or one out of every eighteen adult citizens The active reserve was established by Yuri Andropov in
KGB victim memorials exhibition centre is being created in the former KGB prison in Potsdam. Initially used for interrogating alleged Western spies, some of whom were executed, the prison later mainly held Soviet soldiers who had been arrested for mutiny, desertion or anti-Soviet activity. KGB victim memorials Memorials to victims of the KGB have been set up in several countries that were formerly occupied by the Soviet Union, often in former KGB prisons, to document the repressions of the Soviet secret police and to commemorate its victims. Some are in the form of monuments at the location of KGB prisons or execution sites,