Korea is preparing for a major change to its criminal justice system. A revised law approved in July will abolish prosecutors’ authority to conduct supplementary investigations when the new system takes effect on October 2nd.

Currently, police officers generally carry out the initial investigation. After receiving a case from the police, however, prosecutors may examine witnesses, collect additional evidence, or clarify facts they consider incomplete. These are known as “supplementary investigation rights.”* They help prosecutors decide whether there is sufficient evidence to bring the accused person to trial.

Under the reform, prosecutors will no longer be permitted to fill such gaps themselves. Instead, they will have to ask the police or another investigative agency to conduct further inquiries. The change forms part of a broader plan to separate investigation from prosecution. The current prosecution service will also be replaced by two new agencies. One will investigate serious crimes, while the other will decide whether to file charges.

Supporters argue that this division will prevent excessive power from being concentrated in a single institution. Not only have prosecutors decided whether to indict suspects, but they have also exercised considerable influence over investigations. Advocates believe that the reform will lead to fairer investigations and better control of government power.

Critics, however, warn that this may delay cases. If important evidence is overlooked, a case could move repeatedly between prosecutors and investigators. Some also fear that victims may receive inadequate protection when an initial investigation is incomplete. In particular, complex financial crimes and sexual offenses often require careful follow-up.

The debate is therefore more than about the power of prosecutors. Korea must now determine how independent agencies can cooperate efficiently, while protecting suspects’ rights, supporting victims, and ensuring thorough investigations.

* supplementary investigation rights 보완수사권