Beyond abolishing prosecutors' investigation authority

Kim Ye-won

The author is a lawyer at the Disability Rights Law Center.

The supplementary investigation authority proposed for Korea's new public prosecution office is likely to disappear. The prime minister has referred to its abolition as the government's basic position; the president has left the matter to the National Assembly; and the Ministry of Justice has said that it will not present a separate proposal. The Democratic Party and the Rebuilding Korea Party also support eliminating the authority. Even if exceptions remain, they are unlikely to matter in practice, as few prosecutors would risk legal controversy or personal liability by conducting supplementary investigations themselves.

But the supplementary investigation authority is only one part of the criminal justice system. Preserving it would not solve every problem, and abolishing it would not complete prosecutorial reform. Political debate, however, has become fixated on this single issue while paying remarkably little attention to reforms that matter just as much, including measures to prevent investigative gaps, reduce the number of overlooked cases and clarify institutional responsibility.

If prosecutors lose the authority to conduct supplementary investigations, the more important issue becomes their power to request additional investigations from the police. Simply disciplining officers who ignore such requests will not be enough. Police investigators already face an overwhelming workload, so mechanisms must ensure that supplementary investigations can actually be completed. Certain cases should require review by team leaders, and legally complex matters should receive specialized legal review. Personnel evaluations should also reward thorough and timely follow-up investigations.

Restoring a previous requirement — that all completed investigations be forwarded to prosecutors for review — also deserves consideration. Oversight is not necessary only for major crime cases. Ordinary disputes and seemingly minor cases are often more likely to disappear without meaningful scrutiny. After universal case transfers were abolished and replaced by an objection process, that burden shifted to the citizens. The past five years have demonstrated that filing objections alone cannot provide equal access to justice.

Another priority should be revising the rules of evidence to allow video recordings of suspects' statements made during investigations to be admitted in court. Since prosecutorial and police investigative powers were redistributed, written interrogation records generally lose evidentiary value if defendants later deny their contents during trial. Video recordings, captured early in the investigation when memories are freshest, can be more reliable. But current law provides no clear basis for using those recordings as courtroom evidence, despite the substantial effort required to obtain them.

Clearer rules are also needed to prevent investigative agencies from passing cases back and forth. If the proposed serious crimes investigation office is established, jurisdictional disputes are likely to increase. The greatest risk is that critical early investigations will stall while agencies argue over responsibility. As a result, the law should require prompt decisions on jurisdiction while allowing the agency that first receives a case to continue essential investigative work until responsibility is formally determined. Otherwise, delays may result in lost evidence or expired statutes of limitations.

A recent bill put before the National Assembly would abolish prosecutors' supplementary investigation authority and shorten detention periods during the investigative stage. Whether that is the right approach deserves careful examination. In detention cases, for which prosecutors must decide on indictment within strict time limits, preventing supplementary investigations while reducing detention periods may weaken fact-finding rather than strengthen defendants' rights.

The issue is particularly important as retaliatory crimes become more common. Whether suspects remain in custody can directly affect victims' safety. Instead of relying on uniform reductions in detention periods, lawmakers should consider a more flexible system that reflects the nature of each case and the level of risk involved. Courts could periodically review whether detention remains necessary through regular bail hearings and maintain custody when public safety requires it.

Policymakers should also not assume that courts can correct every investigative deficiency after an indictment is filed. Courts decide cases based on the indictment and evidence presented to them. They cannot identify overlooked accomplices, add omitted charges or gather evidence that investigators failed to secure. Although amended indictments and case consolidation are available, they cannot repair flaws created during the initial investigation.

It is time to move beyond the belief that eliminating one investigative power will complete prosecutorial reform. The real test is not whether a particular authority survives; instead, it is whether criminal cases are handled promptly, thoroughly and fairly and whether responsibility remains clear when mistakes occur.

If the public prosecution office loses its supplementary investigation authority, lawmakers must carefully examine how that change will affect the criminal justice system and present credible alternatives that protect both public safety and due process. Reform introduced without adequate institutional safeguards is unlikely to improve the system and risks becoming reform in name alone.