This study aims to analyze the Brazilian Criminal Investigation, especially regarding the crisis established between prosecutors and judicial police, especially after the Proposed Constitutional Amendment Number 37-A, which, in theory, would restrict the power of investigation the Civil Police State and Federal, and this was strongly opposed by prosecutors, arguing that prevent them from protecting the public interest in combating crime. From this approach, we aim to demonstrate the models also accusatory penal systems, giving focus to the one adopted by Brazil, emphasizing the historical development of police and prosecutors in the Brazilian Constitutions; identify the limits constitutionally imposed on investigative activity, examining the role of the Judicial Police and prosecutors, as well as expose the for and against criminal investigation by prosecutors arguments. At the end, it is shown the at least theoretical impact of the Proposed Constitutional Amendment Number 51 which seeks the demilitarization of the police model. Finally, we conclude the present, demonstrating the importance of joint efforts of police and prosecutors to reach a peaceful society views and social well-being, since the main goal of Criminal Investigation conducted in Brazil is the indication of whether there is sufficient evidence of authorship and materiality of evidence of an offense, which represent essential requirements for a criminal action may be brought and then duly appreciated by the judiciary. Thus, the study developed employs the hypothetical-deductive method and as technical, bibliographic and documentary research.