Previous studies show that political violence often influences individual preferences and attitudes on issues such as securitization and migration. However, the potential impact of political violence on individuals depends on politicized media debates and the reactions of social and political actors to political violence. To gain a better understanding of different responses to political violence and polarisation dynamics in public debates, we study media reactions by political parties following fatal acts of political violence. We compare public debates in the context of central security threats in Europe in recent decades: ETA in Spain (1975-2010) and right-wing and Islamist terrorism in Germany (2000-2020). Within this framework, we investigate agenda-setting effects across parties, polarising issues and frames, and the visibility and resonance of such events. We focus on larger periods before and shortly after an event. Using two mainstream Spanish newspapers and four German newspapers, we draw on quantitative text analysis methods such as topic models to infer which issues are mediatized in combination with specific parties. We implement RDD methods to infer reactions in the partisan mediatized communication caused by political violence. Our results have important implications for our understanding of which social and political actors gain visibility, dominate the political agenda and polarise public debates after acts of political violence.