Drawing on ethnographic data gathered in lower criminal courts and in one unit of the Public Prosecutor's Office in Santiago, Chile, I explore the way in which criminal offenses considered flagrant are treated by the Chilean criminal justice system. Citing the literature on legal technicalities, I describe how flagrant criminal offenses are constructed through practices that make it possible for the actors involved to avoid directly referring to the alleged facts. From their identification on the streets by police officers to their reassignment to a different unit of the Public Prosecutor's Office or their adjudication at a criminal court, flagrant criminal offenses are defined by a specific way of approaching the alleged facts, which is translated into specific organizational and documentary practices. The role of these practices contrasts with the apparently marginal role that the detention in flagrante delicto plays in the mechanics of criminal law. As a technicality, the flagrant character of a criminal offense conveys certain epistemological assumptions about how to determine what happened and what exactly constitutes the criminal offense. More specifically, it conveys assumptions about what cannot, for the moment, be known and that can, therefore, be ignored throughout the bureaucratic and judicial process.