The public security context in Rio de Janeiro is marked by violent dynamics, especially in peripheral areas dominated by criminal groups, such as drug trafficking factions and militias. Although illegal groups represent a source of violence, the violent practices of public institutions, especially the Military Police, are also decisive, exposing the population to extreme actions that disproportionately affect vulnerable areas. However, Brazilian governmentality, especially in the public security sector in Rio de Janeiro, reflects clientelist, corporatist and formalistic patterns, which serve to legitimize extralegal practices and perpetuate structures of impunity. These practices, combined with the discourse of war on crime, create a mosaic of illegal powers that contribute to the reproduction of violence and the strengthening of groups such as militias. Thus, the study seeks to analyze public security policies in Rio de Janeiro between 2000 and 2021, based on the concepts of governmentality (Foucault, 1979) and necropolitics (Mbembe, 2018), in order to understand how these theoretical foundations are applied and generate violent socio-spatial structures. The research demonstrates that the actions of security institutions and clientelist and corporatist networks not only fuel violence, but also legitimize necropolitical practices in the urban context of Rio de Janeiro.