It was one of the most repressive police organisations in the world, infiltrating almost every aspect of life in East Germany, using torture, intimidation and a vast network of informants to crush dissent.

Following the June 1953 uprising, the Politbüro decided to downgrade the apparatus to a State Secretariat and incorporate it under the Ministry of the Interior under the leadership of Willi Stoph.

As intelligence chief, Wolf achieved great success in penetrating the government, political and business circles of West Germany with spies.

The Stasi had also been invited by the KGB to establish operational bases in Moscow and Leningrad to monitor visiting East German tourists.

[16] In 1978, Mielke formally granted KGB officers in East Germany the same rights and powers that they enjoyed in the Soviet Union.

Full-time officers were posted to all major industrial plants (the extent of any surveillance largely depended on how valuable a product was to the economy)[20] and one tenant in every apartment building was designated as a watchdog reporting to an area representative of the Volkspolizei (Vopo).

Tiny holes were drilled in apartment and hotel room walls through which Stasi agents filmed citizens with special video cameras.

Schools, universities, and hospitals were extensively infiltrated,[25] as were organizations, such as computer clubs where teenagers exchanged Western video games.

[27] The roles of informants ranged from those already in some way involved in state security (such as the police and the armed services) to those in the dissident movements (such as in the arts and the Protestant Church).

[29] Informants were made to feel important, given material or social incentives, and were imbued with a sense of adventure, and only around 7.7%, according to official figures, were coerced into cooperating.

[30] The Stasi's ranks swelled considerably after Eastern Bloc countries signed the 1975 Helsinki accords, which GDR leader Erich Honecker viewed as a grave threat to his regime because they contained language binding signatories to respect "human and basic rights, including freedom of thought, conscience, religion, and conviction".

[31] The number of IMs peaked at around 180,000 in that year, having slowly risen from 20,000 to 30,000 in the early 1950s, and reaching 100,000 for the first time in 1968, in response to Ostpolitik and protests worldwide.

[32] The Stasi also acted as a proxy for the KGB to conduct activities in other Eastern Bloc countries, such as Poland, where the Soviets were despised.

[30] The Stasi perfected the technique of psychological harassment of perceived enemies known as Zersetzung (pronounced [ʦɛɐ̯ˈzɛtsʊŋ]) – a term borrowed from chemistry which literally means "decomposition".

It was realised that psychological harassment was far less likely to be recognised for what it was, so its victims, and their supporters, were less likely to be provoked into active resistance, given that they would often not be aware of the source of their problems, or even their exact nature.

[n 1] Anyone who was judged to display politically, culturally, or religiously incorrect attitudes could be viewed as a "hostile-negative"[38] force and targeted with Zersetzung methods.

This often included psychological attacks, such as breaking into their home and subtly manipulating the contents, in a form of gaslighting i.e. moving furniture around, altering the timing of an alarm, removing pictures from walls, or replacing one variety of tea with another etc.

[43] One great advantage of the harassment perpetrated under Zersetzung was that its relatively subtle nature meant that it was able to be plausibly denied, including in diplomatic circles.

[48] This operation helped to strengthen Cuban-East German relations, as well as open up the Stasi to intelligence collected by Cubans in the United States.

[46] The reputation of the Stasi was quite international, with the newly independent nation of Zanzibar making an immediate request for establishing a state security service, and East Germany being the first to recognize the country.

The Politburo decided to help African liberation movements with military and security assistance, under the de facto supervision of Honecker.

On 17 November 1989, the Council of Ministers (Ministerrat der DDR) renamed the Stasi the Office for National Security (Amt für Nationale Sicherheit – AfNS), which was headed by Generalleutnant Wolfgang Schwanitz.

However, the public reaction was extremely negative, and under pressure from the "Round Table" (Runder Tisch), the government dropped the creation of the Verfassungsschutz der DDR and directed the immediate dissolution of the AfNS on 13 January 1990.

[82] The building contained vast records of personal files, many of which would supply important evidence in convicting those who had committed crimes for the Stasi.

[citation needed] They felt that the information in the files would lead to negative feelings about former Stasi members, and, in turn, cause violence.

Pastor Rainer Eppelmann, who became Minister of Defense and Disarmament after March 1990, felt that new political freedoms for former Stasi members would be jeopardized by acts of revenge.

The East Germans knew, of course, that they were surrounded by informers, in a totalitarian regime that created mistrust and a state of widespread fear, the most important tools to oppress people in any dictatorship.

[95][96] Gedenkstätte Amthordurchgang [de], a memorial and 'centre of encounter' in Gera in a former remand prison, originally opened in 1874, that was used by the Gestapo from 1933 to 1945, the Soviet occupying forces from 1945 to 1949, and from 1952 to 1989 by the Stasi.

[109][110] Former Stasi officers continue to be politically active via the Gesellschaft zur Rechtlichen und Humanitären Unterstützung (GRH, Society for Legal and Humanitarian Support).

For example, in March 2006, the Berlin Senator for Education received a letter from a GRH member and former Stasi officer attacking the Museum for promoting "falsehoods, anti-communist agitation and psychological terror against minors".