South Korean prosecutors have recently stepped up publicity over cases they claim were resolved through demands for supplementary investigations. With the Prosecutors' Office set to be dissolved in October following the establishment of a Serious Crimes Investigation Agency and a Public Prosecution Agency, prosecutors losing their posts are mounting a last-ditch effort to preserve their investigative authority. Prosecutors are pushing hard to retain supplementary investigation powers, even publishing a "best practices" compilation, arguing that a check is needed on the police, who will effectively monopolize investigative authority. Police are countering with statistics showing that prosecutorial intervention changes actual outcomes in less than 1 percent of cases, keeping tensions high between the two agencies.
The Supreme Prosecutors' Office recently announced "best practices in judicial oversight." The release included four cases, all of which prosecutors claimed were resolved through demands for supplementary or renewed investigations. A representative example involved a 20 billion won jeonse (a Korean lease system requiring a large lump-sum deposit instead of monthly rent) fraud case, which police had declined to forward on grounds that the requirements for a criminal organization were not met. Prosecutors demanded the case be forwarded and ultimately sent members of the ring to trial.
Cases in which prosecutors have demanded supplementary investigations from police have been increasing recently. On the 24th of last month, the Seoul Southern District Prosecutors' Office rejected an arrest warrant that police had requested for Bang Si-hyuk, chairman of HYBE, on charges of violating the Capital Markets Act through fraudulent unfair trading, and demanded a supplementary investigation. Prosecutors said they "determined that justification for the necessity of detention at this stage was insufficient and therefore demanded a supplementary investigation." The outcome is a painful blow for the police, who launched the probe in late 2024 and applied for the arrest warrant after about a year and a half of continued legal review.
Police expressed displeasure over the move. At a regular press briefing held at the National Police Agency headquarters in Migeun-dong, Seodaemun-gu, Seoul on the 27th of last month, a National Police Agency official said, "Addressing the prosecutors' requests comes first," while also signaling discomfort by adding that "the content of the supplementary investigation demand itself is a matter subject to investigation."
Supplementary investigation demands continue in cases involving everyday life. In a case involving a bus driver who had been forwarded on charges of plowing into a sidewalk near Seodaemun Station intersection in Seodaemun-gu, Seoul in January, injuring 13 people including two pedestrians, the Seoul Western District Prosecutors' Office demanded a supplementary investigation from police on the 1st of last month. In a case involving a former executive at Nonghyup Economic Holdings who, shortly before his retirement in mid-November last year, allegedly molested a female colleague at a restaurant in Yeongdeungpo-gu, Seoul, the Yeongdeungpo Police Station declined to forward the case citing insufficient evidence, prompting the Seoul Southern District Prosecutors' Office to order a renewed investigation. Police have since resumed the probe.
As prosecutors have recently taken actions including releasing consecutive materials related to supplementary investigations, police have also responded in an unusual manner. On the 21st of last month, when the Wonju branch of the Chuncheon District Prosecutors' Office designated as a human rights protection best practice a case in which it indicted and detained a teenage suspect in the "attempted murder of three women in a family" case in Wonju, Gangwon Province, the Gangwon Police Agency immediately pushed back. The Gangwon Police Agency said in a statement on the matter that it had conducted digital forensics on the suspect's mobile phone and forwarded key evidence to prosecutors, including search records related to murder and sexual exploitation videos. The message was that much of the content in the material released by prosecutors had already been secured through police investigation.
In addition, the Wonju Police Station under the Gangwon Police Agency recently sent back to prosecutors a health crime crackdown suspect case for which the Wonju branch of the Chuncheon District Prosecutors' Office had demanded a supplementary investigation. Wonju Police Station publicly returned the prosecutors' demand, saying, "For certain cases, prosecutors promote and showcase their investigative authority while emphasizing the need for supplementary investigation powers. But for the many straightforward public complaint cases, they don't even comply with relevant regulations, raising the question of whether they effectively view the police as a subordinate agency."
Police maintain that prosecutors' supplementary investigation achievements have been inflated. At the "Desirable Prosecutorial Reform Seen by the Police" forum held at the National Assembly on the 29th of last month, Song Ji-heon, head of the Seoul Metropolitan Police Agency's investigation review team, said that only 2,189 cases out of a total of 236,911 had their forwarding or non-forwarding opinions overturned through prosecutors' demands for supplementary or renewed investigations. In particular, Song argued that cases in which prosecutors demanded supplementary investigation citing the necessity of indictment, resulting in a change to a forwarding opinion, amounted to just 455, or 0.17 percent of the total.
However, given recent unfavorable perceptions of the police, some argue that police must build the capacity to handle an influx of cases without prosecutorial oversight. A representative example is the case of independent lawmaker Kim Byung-kee, who faces a total of 13 allegations of misconduct, including preferential admission of his second son to Soongsil University, preferential medical treatment for family members, and suspicions of nomination bribes. More than six months have passed since the allegations were raised in September last year, but none of the numerous cases related to Rep. Kim have yet left the hands of the police. When criticism of delayed investigation emerged, police said they would sequentially reach conclusions, starting with allegations where guilt or innocence could be determined in the near term. But more than three weeks later, no particular news has been heard. In the Coupang personal data leak case, police formed an 86-member task force in January to investigate, but no conclusion has been reached. Allegations that Kang Ho-dong, chairman of Nonghyup Holdings, received illicit payments are similarly stalled.
Internal misconduct issues have also surfaced. Allegations of drunk driving, sexual misconduct, and even investigation cover-ups have emerged, with lax discipline within the police further shaking the agency. On the 21st of last month, a police officer from Seogwipo Police Station was dismissed on charges of driving while heavily intoxicated on a road in Nohyeong-dong, Jeju City, and colliding with a vehicle waiting at a signal. On the 16th of last month, the Seoul Metropolitan Police Agency placed a precinct officer suspected of molesting a subordinate on standby duty. There was also an unprecedented case in which a current police officer was investigated on suspicion of covering up an investigation in exchange for bribes.
The issue of prosecutors' supplementary investigation powers is expected to remain unresolved for the time being. The debate is sharply divided between the view that prosecutors, who hold the power to indict, need to verify facts necessary for indictment directly and that institutionally blocking this would be unfair, and the view that supplementary investigation powers must be abolished for genuine prosecutorial reform. Broader social discussion is needed. The ruling bloc plans to begin full-fledged discussions on the Criminal Procedure Act amendment after the local elections scheduled for the 3rd of next month, when it will determine whether to retain supplementary investigation powers.
