Disagreement Over Direct Supplementary Investigation Authority: "Effectively Direct Investigative Power" vs. "Should Be Regulated, Not Abolished"

Prosecution Reform Team Holds Discussion on "Supplementary Investigation and Supplementary Investigation Requests"

Attorney Kang Dongpil: "Direct Supplementary Investigation Authority, a Backdoor for Abuse of Investigative Powers"

Professor Kim Sanghyun: "Judgments Formed Solely Based on Unilateral Police Records"

Experts were divided over the necessity of retaining the direct supplementary investigation authority of prosecutors at the Prosecution Office following the adjustment of investigative powers. On one side, critics argued that direct supplementary investigative powers run counter to the intent of prosecution reform, while supporters claimed they are essential for maintaining prosecutions.

Yoon Changryul, Director of the Prosecution Reform Promotion Team and Secretary-General of the Office for Government Policy Coordination (left), is delivering a greeting at the "Discussion on Supplementary Investigation and Requests for Supplementary Investigation from the People's Perspective" held at the HJ Business Center in Jongno-gu, Seoul on the 16th. Photo by Kang Jinhyung

The Prosecution Reform Promotion Team held a discussion on the topic of "Supplementary Investigation and Supplementary Investigation Request from the People's Perspective" at the HJ Business Center in Jung-gu, Seoul, on the afternoon of March 16, 2026.

Kang Dongpil, an attorney at Barun Law LLC and the first presenter, argued that prosecutors’ direct supplementary investigation authority effectively neutralizes prosecution reform. He insisted that the regulation allowing prosecutors to conduct direct supplementary investigations should be abolished and that the Prosecution Office must be fully transformed into an organization without investigative functions to align with the spirit of reform.

Attorney Kang stated, "Although supplementary investigation authority does not allow prosecutors to initiate investigations, there is no restriction on the scope of voluntary or compulsory investigations within the case or related cases. The term 'supplementary' is merely a label; the essence of direct investigative power remains unchanged." He further pointed out, "In particular, the lack of any mechanism to control supplementary investigations by prosecutors could become a 'backdoor' for abuse of investigative powers."

He also rejected the criticism that delays in investigations are due to the reduction of prosecutors’ supplementary investigative powers. Kang explained, "Even after the adjustment of investigative powers in 2021, the prosecution refused the transfer of personnel, and there was no increase in personnel or budget support. The only accurate solution to prolonged cases is an increase in manpower."

On the other hand, Kim Sanghyun, professor at Korea University Law School and another presenter, emphasized the inevitability of supplementary investigations to maintain prosecutions. Under the theme "Can Prosecutors at the Prosecution Office File Charges Based Only on Records?" Professor Kim argued, "If supplementary investigation authority is stripped away, prosecutors will have no choice but to form their judgment solely based on unilateral police records, without any direct review. Prosecutors, as the party responsible for prosecutions, need the authority to conduct supplementary investigations in order to fill gaps in the evidence in court."

He added, "If the review is limited to documents, the rate of misjudgment in deciding whether to file charges will naturally increase. There will be more cases where it works against the suspect, and the resulting human rights violations are inevitable."

In response to concerns about the abuse of supplementary investigation authority, he countered, "Rather than abolishing the power, it should be regulated through procedural controls and a more sophisticated system of accountability."

During the designated discussion that followed, panelists also displayed differing views on the necessity of direct supplementary investigative authority. Kim Jaeyoon, Dean of Konkuk University Law School, and Yoon Dongho, professor at Kookmin University Law School, stressed that the fundamental principle of "separation of investigation and prosecution" in investigative system reform must not be compromised. They argued that, instead of granting direct supplementary investigation authority to prosecutors, institutional improvements should be made to enhance the effectiveness of requests for supplementary investigation.

Conversely, Jeon Byeongdeok, attorney at Gangnam Law LLC, and Jeong Jaegi, attorney at Brighton Law Office, pointed out the problems caused by the so-called "investigation ping-pong" phenomenon in practice. They argued that in order to prevent investigation delays and protect the fundamental rights of the people, prosecutors' direct supplementary investigation authority should be retained.

This content was produced with the assistance of AI translation services.