A Critical Review on the Separation Theory of Investigation and Prosecution: Focusing on comparative legal perspective
Authors:   The Korean Association of Criminal Procedure Law, Lee Chang-On 
Published: October 2022

Investigation should not have any meaning on its own, apart from the prosecuting authority’s decision. This is because these judgments can not be properly made unless the legal and normative viewpoints of the prosecuting authority are applied. There is no purpose of investigation itself, and there should not be because there is no reasonable grounds in terms of protecting constitutional rights and human rights that the independence of the investigative authority should be guaranteed. Therefore, if the purpose of the investigation is to evaluate the possibility of proving guilt and to decide whether to initiate a prosecution, and the validity of the decision is ultimately evaluated by the court's decision or judgment through the trial process. the authority and responsibility of the investigation should belong to the prosecuting authority according to the principle of purposiveness and the principle of professionalism. If the organizational structure and authority are set so that the incentives and decision-making of the members in the organization are contradictory to each other in the areas with the same purpose and function, serious disharmony and burden will occur within the system. Whether the legal nature of the investigation of a specific case is judicial or administrative depends on the philosophical and institutional perspectives with which how important and realistically achievable the culture of the relevant legal system regards the fairness of the investigation procedure. The ideal investigative agency for which our Constitution and the Criminal Procedure Act aims should only discover the actual truth and implement judicial justice, while maintaining objectivity and neutrality in criminal procedures. Investigation should not be used to achieve administrative purposes, but are aimed only at finding the truth and the judicial justice. To achieve this, the investigation should not be part of the administration, but should be part of a judicial or quasi-judicial power independent of the administration in our criminal legal system. If real-world prosecutors fail to realize quasi-judicial independence in spite of these legal ideals and institutions for achieving them, a device that can guarantee independence and objectivity of them should be developed in order to properly implement this ideals. The investigative authority should not be monopolized by administrative agencies that are bound by the principles of administrative authority and purposiveness. Most of the existing problems raised with respect to the prosecutor's concentration of power should have been addressed with the standpoint of strengthening the independence and neutrality of the prosecution service and refraining from unnecessary direct investigations, thereby solidifying their identity as a quasi-judicial institution. In addition, it should have been approached by strengthening the objective measures of checks and independent inspection procedure in the decision-making process of the prosecution service regarding investigations and prosecutions. Separating investigation and prosecution and weakening the prosecuting authority's command and control against the investigation agencies should not have been considered in the first place. The system as a whole has made it easier for front-line investigative agencies to abuse their investigative powers with this new approaches. This accumulates burdens on the criminal system that can not be sustainable in the mid- to long-term and could disrupt our criminal justice system which maintains the fundamental characteristics of the continental inquisitorial system so that the prosecution guarantees the completeness of the investigation in an objective and neutral position,