
This paper aims to analyze the impact of custody hearings on the practice of criminal law in Rio de Janeiro, considering the conduct of this procedural protocol from the perspective of system operators. In this sense, data from a survey that combined methodological instruments in order to understand the perception of lawyers working in the criminal sphere of Rio de Janeiro regarding the practices of judicial institutions in conducting Custody Hearings are presented. The application of virtual questionnaires and open interviews indicate that custody hearings are ineffective in controlling the legality of the arrest by recognizing nullities. Furthermore, it asserts the difficulties of changing a decision on arrest/release during the trial of the case, as well as in the context of Habeas Corpus. Thus, it is concluded that the protocol cooperates to reinforce the presumption of guilt of the defendant, enabling the early fulfillment of the sentence, and making reported situations of police violence invisible. The data also draw attention to the fact that the predictability of decisions also guides the practice of criminal law.