Yoon faces mounting trials and special probe despite first conviction becoming final

Former President Yoon Suk Yeol received a final guilty verdict Thursday — 583 days after he declared emergency martial law on Dec. 3, 2024 — as the Supreme Court upheld a seven-year prison sentence on charges that he obstructed the execution of an arrest warrant by the Corruption Investigation Office for High-ranking Officials. The ruling closed one of eight separate trials Yoon has been facing since the martial law declaration. Yet the second comprehensive special prosecutor's office — led by Special Prosecutor Kwon Chang-young — is pressing ahead with investigations into additional allegations against him, raising the prospect of further charges and trials.

According to legal sources, the special prosecutor's team is investigating Yoon on charges of abuse of authority in connection with allegations that he directed officials to spread messages justifying the martial law declaration to allied nations after it was imposed. That aspect of the case was not indicted in earlier special prosecutor investigations.

The Supreme Court's Third Division, presided over by Justice Lee Suk-yeon, confirmed Thursday the lower court's sentence of seven years in prison for Yoon on charges including obstruction of official duties. The case centered on allegations that he mobilized the Presidential Security Service to block the CIO from executing an arrest warrant during the martial law investigation. It was the first of his eight ongoing trials to reach a final verdict.

Beyond the warrant-obstruction case, Yoon is still standing trial on charges of leading an insurrection, general treason, perjury, interference in the investigation into the death of a Marine Corps corporal, aiding the flight of former Defense Minister Lee Jong-sup, involvement in the so-called Myung Tae-gyun gate, and making false statements during the 20th presidential election. Yoon was attending a hearing at the Seoul High Court on the insurrection leadership charges when the Supreme Court handed down its ruling Thursday, and the court briefly recessed to allow him to watch the verdict. He was seen giving a hollow laugh when the seven-year sentence was confirmed.

The number of trials Yoon must face could grow again, however. The special prosecutor's investigation targeting his remaining alleged offenses is still ongoing.

The special prosecutor's team has booked Yoon on suspicion of spreading messages to justify the martial law declaration and on charges of mutiny under the Military Criminal Act. He is alleged to have directed the National Security Office, the National Intelligence Service and the Ministry of Foreign Affairs to convey to the United States and other allied countries the message that the martial law declaration was justified, shortly after it was imposed. The team applied charges of abuse of authority on the grounds that he compelled civil servants to perform acts outside their official duties.

The team questioned Yoon as a suspect on June 6. During the questioning, he is said to have maintained that the emergency martial law was lawful — pushing back against characterizations of it as unconstitutional or illegal — and to have stated that he told officials to inform foreign governments because the declaration was legitimate, thereby denying the abuse-of-authority charges.

In connection with those allegations, former National Security Office chief Shin Won-sik, former first deputy chief Kim Tae-hyo, former NIS director Cho Tae-yong and former NIS first deputy director Hong Jang-won have come under investigation. Hong has drawn particular attention: unlike the earlier insurrection special prosecutor's office led by Cho Eun-seok, the current team booked him as a suspect rather than a witness, given that he testified at Yoon's impeachment trial about orders to arrest politicians. Whether he ultimately receives a guilty verdict is being closely watched.

The special prosecutor's team is also investigating Yoon on charges of mutiny under the Military Criminal Act — a step the earlier insurrection special prosecutor did not take. Attorney Kim Gyeong-ho had previously filed a complaint with the team arguing that Yoon and others should be indicted on charges of leading a mutiny under the Military Criminal Act, contending that prosecuting them solely under the Criminal Code's insurrection provisions was legally incorrect.

The team has, however, tentatively decided not to indict Yoon on the Military Criminal Act mutiny charges, concluding that doing so while he is already indicted on insurrection leadership charges under the Criminal Code could constitute double jeopardy. Deputy Special Prosecutor Kim Jeong-min said Thursday that the team had "reviewed whether it would also affect the insurrection special prosecutor's indictment."

The team is also examining whether the presidential office under Yoon intervened in the Marine corporal death case. The allegation is that the presidential office was involved in the Defense Ministry's retrieval of the case from police in August 2023, after the Marine Corps investigation unit had transferred it. The team questioned former presidential office public integrity secretary Lee Si-won as a suspect on June 25.

The team is additionally looking into whether the presidential office interfered in the Seoul Central District Prosecutors' Office's 2024 decision not to indict first lady Kim Keon Hee over allegations of stock price manipulation involving Deutsch Motors. Former Prosecutor General Shim Woo-jung, former Seoul Central District Prosecutors' chief Lee Chang-su and former head of the office's anti-corruption investigation unit Choi Jae-hun are among those under scrutiny. On Tuesday, the team questioned former presidential office personnel secretary Lee Won-mo as a reference witness. The team is said to have pressed him on allegations of so-called "VIP treatment" — a reference to prosecutors summoning Kim to a government building rather than a prosecutors' office and conducting a non-public interview there.

Questions about the team's investigative capacity and competence have nonetheless persisted. The team has said it is pursuing a "heavy-tail" strategy — concentrating arrests and indictments in the latter phase of the investigation — which it says necessarily means fewer such actions early on. But after exhausting its basic 90-day investigation period and two 30-day extensions, it has now asked the National Assembly to amend the law to grant a further extension.

While the issuance of an arrest warrant does not constitute a guilty verdict, courts have continued to reject warrant applications on grounds of insufficient substantiation of charges. In one notable instance, the team sought warrants to detain former Korea Coast Guard chief Kim Jong-uk and former planning and coordination chief Ahn Seong-sik on allegations of involvement in the martial law declaration, but the court rejected them, saying "there is room for dispute over the criminal charges."

On June 23, the team sought an arrest warrant against the head of a company called 21 Grams on charges of abuse of authority in connection with allegations surrounding the relocation of the presidential residence, but the court rejected it. The team had previously made public other warrant applications, but it did not disclose either the application or the rejection in the 21 Grams case, drawing criticism for selective disclosure.