Were any members of the Stasi prosecuted, or were there instances of blanket amnesty, after the fall of the Berlin Wall and subsequent German reunification?
For the most part, the 91000 employees of the Ministerium für Staatssicherheit (MfS, aka Stasi) were put to pasture during the process of reunification. There was some attempt by the Federal Republic to prosecute various MfS agents for crimes committed under the auspices of the GDR, but they generally fizzled out. The example of foreign intelligence head Markus Wolf is instructive for how trials of MfS figures proceeded. The lower German courts convicted Wolf for treason, torture and other violations of civil liberties, but the Bundesgerichtshof (German Federal Constitutional Court) overturned the conviction on the basis that Wolf was acting on behalf of a sovereign power at the time. Likewise, the FRG tried to bring MfS head Ernst Mielke to task for his actions. He was convicted for the murder of two police captains in 1931 and later brought to trial for the shootings of defectors, but Mielke's advanced age and seeming senility led to a ruling that he was not fit to stand trial. As the Mielke and Wolf trials demonstrate, it was hard to bring MfS agents to trial since this brought up a tangle of legal issues. It was difficult for FRG courts to retroactively apply West German law onto these individuals and the few trials brought to court became bogged down in legal minutia of jurisdiction.
Although they were largely free from successful prosecutions, MfS employees did not weather the reunification process very well. In the early stages of reunification in early 1990, MfS General Gerhard Niebling floated a deal in which the MfS would get amnesty and some post-unification existence in exchange for promises not to interfere with the unification process and sharing all its data it had on Western governments. This deal fell through largely because of opposition from the various GDR citizen's committees and the wider hatred the bulk of the GDR 's population held for the SED's security apparatus made such an amnesty deal a dead letter.
The dissolution of the MfS was of a piece with how the FRG approached the amalgamation of the GDR's civil servant with their Western counterparts. The attitude of the FRG bureaucrats was that the large staffs and personnel that typified GDR state employment was an economic liability and needed to be cut. For civil servants in relatively innocuous fields like the the post office or academia, it was possible for an individual GDR civil servant to find work in their new unified civil service. But for civil servants in state entities closely associated with propping up the SED dictatorship such as the MfS or the Nationale Volksarmee (NVA), the attitude of the FRG was that these individuals were morally compromised by the SED. In the case of the NVA, individuals above the rank of lieutenant-colonel were not considered acceptable candidates for service in the post-1990 Bundeswehr. So for the MfS, continuing to ply their trade in German intelligence was not an option.
Some 1500 low-level MfS employees did transfer into the new federal police, especially the Federal Border Guard. Others found a home in the local civil service of the eastern federal states, especially as mid-level bureaucrats in unemployment offices. However, the majority of the former MfS employees ended up in the private- and semi-public sector. Some of these jobs were relatively prestigious, but other jobs like night-watchmen were an ignominious end for what had been a state elite. Although the federal government does pay their pensions ( a fight that the FRG lost in court), the pay level is considerably lower than the pensions they would have received in the GDR.
The low status and negative public perception of the MfS in unified Germany has been the source of much bitterness for MfS members. Overall, institutions like the MfS or the NVA have been relatively immune from the Ostalgia trend. This elegiac celebration of the GDR, as exemplified by films like Goodbye Lenin, prefers to valorize aspects of daily life and the commitment of "regular" GDR citizens to issues of social justice. Given this situation, many MfS veterans have formed their own special interest lobbies, such as the Joint Initiative for the Protection of the Social Rights of Former Members of the Armed Organs and the Customs Administration of the GDR (ISOR). Despite the fact that MfS veterans are active and vocal in the German left, but these groups are relatively socially isolated from the unified body politic. interviews with a number of MfS and NVA veterans feel they have been unjustly scapegoated for the excesses of the SED and some individuals even liken their position in the unified Germany to that of Jews in the Weimar Republic and Third Reich- which is a gauche and rather distorted view of German history.
Sources
Bruce, Gary. The Firm: The Inside Story of the Stasi. Oxford: Oxford University Press, 2010.
Caldwell, Peter C., and Robert R. Shandley. German Unification Expectations and Outcomes. Basingstoke: Palgrave Macmillan, 2011.
Gieseke, Jens. The History of the Stasi: East Germany's Secret Police, 1945-1990. New York: Berghahn Books, 2014.