Han Moon-hyuk, who was the head of the investigation team for the Deutsche Motors stock manipulation case, has been issued a warning by the Supreme Prosecutor's Office (SPO) for having previously participated in a drinking session with Lee Jong-ho, a key suspect in the case. Following the controversy, Han was removed from his duties with the special investigation team that was looking into allegations involving Kim Geon-hee, the spouse of South Korea's president, and was recently demoted to a position at the Suwon High Prosecutor's Office. The SPO concluded its investigation into Han's conduct on September 9, delivering the warning that serves as a reprimand just short of a more severe disciplinary measure.

The SPO's internal review confirmed that Han had met with Lee, who was managing accounts for Kim Geon-hee, in August 2021 while part of the Deutsche Motors investigation team. Han failed to report this personal meeting to his superiors during the ongoing investigation in the first half of last year. This failure to disclose was corroborated by a decision from an oversight committee composed mostly of external members, indicating serious misconduct. Han took over the investigation into the Deutsche Motors case in September 2021, just a month after his meeting with Lee, and participated in a renewed investigation in April last year.

In defense of his actions, Han has stated that he was unaware of Lee's involvement in the case at the time of their drinking session, as Lee was not mentioned in any investigative records until a later date. However, Lee's testimony contradicts this claim, as he recounted that Han had directly introduced himself as the head of the investigation team, implying that Han knew of Lee's identity and the relevance of their meeting to the ongoing investigation, further complicating Han's defense and raising questions about his integrity in handling high-profile cases within the prosecutor's office.