The present work aims to explore existing or possible forms of interaction between agents of public security and private security agents within the scope of the state of Rio de Janeiro, being understood as agent the person, the group or the company that is dedicated that engages in that activity. The research object is linked to the relationships of agents who legally carry out the activity, although it does not exclude any illegal activities that may be practiced by them whenever they bring relevant reflections. Although cooperative relations are the most recurrent theme in this context, the legal and politically contradictory aspects of this relation with their consequences in the respective fields are emphasized here. It is not intended to exhaust the relationship patterns between the agents mentioned, but to undertake their examination, it is necessary to go through the analysis of institutional aspects, which will leave the reader prone to new conclusions. Therefore, a brief analysis is made of the legal structure of the agents at play, as well as of their political activities, emphasizing - as far as the police are concerned - their militarized branch, due to the similarities it has with private security and its role ostensive. The paper also uses interviews and procedural and statistical research to corroborate (or not) the ideas presented. The main hypothesis is that the dynamics of military police action have been altered by the expansion of private security services, without fatalistic pretensions. Faced with this, the work exposes patterns that may lead to the unconstitutionality of some policing programs.