Based on more than a decade of research on perpetrators, in particular in Rwanda, this critical reflection underlines the value of studying perpetrators for examining the empirical dynamics of genocide and mass violence. At the same time, the essay also points to three potential limitations of perpetrator-centred research: 1. Can social scientists really understand acts of killing and mutilation? 2. Does the application of ‘perpetrator’ unwittingly foster a selective notion of history and encourage Manichean hierarchies in the interpretation of the past? 3. Analysing perpetrators, especially mid- and lower level ones, may not be insightful for thinking about the origins of genocide.