T The criminal justice mechanism in indonesia constitutes a legal process governed by the criminal procedure code (kitab undang-undang hukum acara pidana or kuhap), which serves as formal criminal law. the criminal justice process proceeds through stages of preliminary investigation (penyelidikan) and investigation (penyidikan) to determine whether a criminal act has occurred. this process is carried out to obtain and collect the necessary evidence in accordance with the provisions stipulated in kuhap. once sufficient evidence has been gathered, the process moves to the investigation stage, at which point the case is considered ready to proceed to the next phase.in the course of investigation as part of the criminal procedural mechanism, there remains the possibility of abuse of authority that does not conform to the procedures established and regulated by statutory law. therefore, the existence of the pretrial institution (praperadilan) is essential as a supervisory mechanism to ensure the protection of the rights of parties who may suffer harm as a result of such abuse of authority.