section_path: Aftermath/Impeachment, arrest, and indictment/Legal investigations
section_name: Legal investigations
paragraph_text: Legal investigations
  
  The DPK sought then Defense Minister Kim Yong-hyun's impeachment for proposing martial law to Yoon, and intended to file a criminal complaint against him. The party's chief spokesperson, Jo Seoung-lae, issued a statement saying "The DPK will punish the unconstitutional and illegal emergency martial law of the Yoon administration We urge law enforcement agencies to immediately launch an investigation into the treason case that the entire nation is now aware of and bring the perpetrators to justice". On 5 December, the police investigated Yoon and other key officials for alleged insurrection in response to a case filed by minor opposition parties and 59 activists accusing them of treason. Defense Minister Kim Yong-hyun resigned the same day and issued an apology. "First, as defense minister, I feel deeply responsible and sorry for causing concern and confusion in regard to the martial law," he said. "All members of the armed forces involved in the implementation of the emergency martial law only did their duty at my direction. I take full responsibility for it." The DPK planned to appoint a permanent special counsel to investigate Yoon for treason and considered filing charges against PPP Floor Leader Cho Kyung-ho, who urged PPP lawmakers to assemble at the party's headquarters rather than the Assembly.
  
  On 8 December, former Defense Minister Kim Yong-hyun was arrested on suspicion of committing insurrection by advising Yoon to declare martial law and sending troops into the National Assembly to seize the legislature. On the same day, Democratic Party lawmaker Choo Mi-ae publicly revealed that Kim's favorite book to read was Adolf Hitler's autobiographical manifesto Mein Kampf, which added to suspicion that Kim, having risen to such a powerful position within both the military and the government, may have been driven by darker instincts rather than a sense of duty to national security. The Ministry of Justice barred Kim from leaving the country following rumors that he booked a flight to flee overseas to avoid prosecution. He could potentially be sentenced to life in prison, or the death penalty if found guilty.
  
  On 9 December, the Ministry of Justice issued an overseas travel ban against Yoon following an investigation into allegations of rebellion linked to his brief imposition of martial law, marking the first instance of a sitting president facing such restrictions. That same day, Lee Jae-myung issued a statement exonerating lower-ranking soldiers who participated in the martial law exercises and expressed gratitude for their restraint, saying that they had been "exploited" by their commanders. An overseas travel ban was placed on KNP Commissioner Cho Ji-ho, Seoul Metropolitan Police Agency Chief Kim Bong-sik and Mok Hyun-tae, head of the National Assembly Police Guards, as part of the martial law investigation.
  
  On 10 December, the National Assembly passed a bill creating a permanent special counsel to investigate Yoon on charges of treason related to his martial law declaration. The motion passed with 210 MPs, including 23 PPP members, in favor after the party allowed its members to vote according to their individual decision. That same day, Army Maj. Gen. Moon Sang-ho, chief of the Defense Intelligence Command, was suspended over his role in the incursion into the National Election Commission's office in Gwacheon.
  
  On 11 December, KNP Commissioner Cho Ji-ho and Seoul Metropolitan Police Chief Kim Bong-sik were arrested without a warrant on charges of insurrection. On 12 December, Park An-su was suspended as Army Chief of Staff.
  
  On 12 December, in a plenary session, the National Assembly passed a bill calling for a special counsel probe into the insurrection charges against Yoon. On the same day, a special police investigation team and the Defense Ministry's investigation unit jointly raided the Defense Ministry and the Capital Defense Command, securing a "secret phone" of Kim Yong-hyun and the phone's server data.
  
  On 13 December, a court formally issued arrest warrants for KNP Commissioner Cho and Seoul Metropolitan Police Chief Kim, citing concerns over evidence tampering. That same day, Capital Defense Command head Lee Jin-woo was also arrested.
  
  On 14 December, prosecutors arrested DCC chief, Lt Gen. Yeo In-hyung.
  
  On 16 December, police arrested Defense Intelligence Command chief Maj. Gen. Moon Sang-ho over his role in the NEC raid. His predecessor, Roh Sang-won was also arrested on suspicion of helping Yoon draft his martial law plans in a civilian capacity. That same day, a military court ordered the arrests of Lt. Gen. Kwak Jong-geun, former chief of the Special Warfare Command and Lt. Gen. Lee Jin-woo, former head of the Capital Defense Command.
  
  On 17 December, Park An-su was arrested following a warrant.
  
  On 26 December, the defense ministry suspended Brig. Gen. Koo Sam-hoe, commander of the Army's 2nd Armored Brigade, and Brig. Gen. Bang Jeong-hwan, head of the ministry's operational control transition task force, for their role in the planning of martial law and Koo's attempts to mobilize a tank unit.
  
  On 27 December, the National Assembly voted 191–71 to create a special committee to investigate insurrection charges against Yoon, with a tenure lasting until 13 February 2025. The committee was formally opened on 31 December and was composed of 18 lawmakers, including 10 opposition and seven PPP lawmakers and one independent lawmaker. It was chaired by DPK MP Ahn Gyu-back, with Kim Sung-won as committee secretary for the PPP. Among the agencies to be called for questioning were the presidential office, the Office of National Security, the Presidential Security Service, the Prime Minister's Office, the Supreme Prosecutors Office, the defense, interior and justice ministries, the National Police Agency, the National Intelligence Service and the Defense Counterintelligence Command.
  
  On 15 January 2025, former colonel Kim Yong-gun was arrested for allegedly plotting the martial law declaration with former Defense Minister Kim and former intelligence commander Roh Sang-won. He was indicted on abuse of power and obstruction of justice charges the same day.
  
  On 5 February, the National Assembly planned an on-site questioning session at the Seoul Dongbu Detention Center, aimed to directly question key figures involved in the martial law declaration, but it was cancelled after Kim Yong-hyun refused to cooperate. Despite his witness chair already being set up, Kim declined to appear at the session, insisting that he could not attend it due to "trial preparation." Kim had previously refused to attend any parliamentary hearings held by the special committee. Democratic party member Ahn Gyu-back apologized to the committee for Kim's behavior, and added that the committee would file a complaint against Kim for contempt of the Assembly at next week's plenary session. Democratic Party representative Han Byung-do would also voice his annoyance, stating; "Refusing to cooperate with the investigation is an outright rejection of the truth. If he is so confident and honorable, why can’t he stand in front of the public?" Later that afternoon, lawmakers visited the Seoul Detention Center to hold another questioning session with President Yoon and Roh Sang-won, however the session was also cancelled when Yoon also declined to cooperate.
  
  On 6 February, the defense ministry placed Yeo In-hyung, Lee Jin-woo, Kwak Jong-keun, and Moon Sang-ho on compulsory leave of absence following an ongoing criminal investigation against them over martial law.
  
  On 17 February, a criminal investigation into first lady Kim Keon-hee was called for alleged involvement in the martial law declaration to cover up election interference.
  
  On 21 February, Kim Yong-hyun applied for a suspension of execution in protest of the prosecution's sending of his prosecution's investigation records to the Constitutional Court, but it was rejected.
  
  On 28 May 2025, former Commander of the Defense Intelligence Command Roh Sang-won was indicted on bribery charges, which revealed that he, along with former Defense Minister Kim, were accepting bribes and valuables back in August 2024 from active-duty soldiers under the pretext of requesting promotions.