The study analyzes political denunciation in the GDR from multiple perspectives: It differentiates between the communicative specifics of letter, telephone and personal appearance at the police station - as well as in the institutional context of organized informal activity. She develops a typology of unofficial employees of the state security based on the denunciation content of the transmitted information. Another aspect is the acts of betrayal in different social contexts - in the family, among friends, at work or among strangers - which differ significantly in terms of the loyalties involved. The question of the motives of the informers is of enormous social interest, but can only very rarely be answered precisely on the basis of the sources. Therefore, the author concentrates on identifying the argumentation topoi used by the informers for self-justification.