Jang Yun-gi case reignites debate over prosecutors' supplementary investigation powers

Evidence that police conducted a shoddy investigation into Jang Yun-gi — who brutally murdered a high school girl he had never met — has reignited a fierce debate over prosecutors' supplementary investigation powers.

What the police record alone would have treated as a straightforward murder case yielded grounds for a rape-murder charge only after prosecutors conducted supplementary investigations. The revelation that police may have systematically tried to cover up the case has deepened the controversy. Police maintain that isolated incidents should not be conflated with the broader debate over supplementary investigation powers, while prosecutors have grown louder in calling for those powers to be retained.

Within the police, the prevailing view since the Jang case emerged is that it should not be linked to the question of whether prosecutors retain supplementary investigation authority. Officers argue the case should be resolved through internal discipline, not used as a pretext to reverse the push to abolish those powers.

"Wrongdoing, once confirmed, must be met with strict punishment — but isolated incidents in a regional office should not be generalized as a problem with the entire police force," a police official said. "The reason investigative authority was realigned in the first place was that the side effects when prosecutors conducted investigations directly were far greater." Another senior police official said prosecutors were "twisting this case to their own advantage" to justify keeping supplementary investigation powers.

The National Police Officers' Labor Council also issued a statement Wednesday, saying "attempts to deny the investigative capacity of the entire police force based on specific cases and to reverse the direction of criminal justice reform cannot be seen as an approach that serves the public," and vowing to "firmly resist any attempt to use isolated cases to roll back criminal justice reform."

After prosecutors' supplementary investigation raised the possibility that police had organized a cover-up, the Korean National Police Agency launched its own fact-finding effort. The agency dispatched investigators from the National Investigation Headquarters to the Gwangju Metropolitan Police Agency to form a special investigation team, and relieved of duty the head of the investigative unit at the Gwangju Gwangsan Police Station — identified by the surname Park, holding the rank of inspector — who had handled the Jang case. National Investigation Headquarters chief Hong Seok-gi told reporters Monday that he was "at a loss for words" and pledged to stake his career on getting to the truth of the case.

However, some have raised concerns about the structural limitations of having police investigate police misconduct. "For the sake of credibility alone, it would be preferable for investigations into the police to be handled by a third investigative body," one police official said.

Inside the prosecution, the Jang case is being cited as evidence of the need for oversight of police investigations. Prosecutors say supplementary investigations frequently uncover facts missed during the initial police inquiry.

"The Jang case drew wide attention, but cases with problems at the initial investigation stage are overflowing even now," a senior prosecutor said. "If supplementary investigation powers are abolished entirely and this keeps happening, who will be held responsible?" A prosecutor at a district office said the case was "a comprehensive exposure of the problems that can arise when police investigations go unchecked," adding that "on the front lines, we investigate cases every day that would be buried without supplementary investigation."

A prosecutor in a district office's women and children crimes unit wrote on the prosecution's internal network: "Even judges hear testimony directly before ruling on guilt or innocence — yet a prosecutor without supplementary investigation powers cannot hear from the parties to a case. If a prosecutor must decide whether to indict based solely on the police record, what judicial oversight does the police investigation actually receive?"

Independent lawmaker Han Dong-hoon warned on social media Wednesday that the Jang case "starkly illustrates that if only police are allowed to investigate, countless victims could be left without recourse," cautioning against abolishing prosecutors' supplementary investigation powers.

The ruling party, however, signaled it would press ahead, calling abolition an "unwavering principle." A criminal procedure law amendment bill sponsored by National Assembly Legislation and Judiciary Committee chairwoman Seo Young-gyo and Democratic Party of Korea lawmaker Kim Yong-min, along with other pro-ruling-party lawmakers, was submitted to the Assembly's judiciary committee Wednesday. The bill would strip prosecutors of investigative authority entirely and transfer the primary role of investigation from prosecutors to police.