President Yoon Suk Yeol is taken to the Seoul Detention Center after being interrogated at the Corruption Investigation Office for High-ranking Officials in Gwacheon, Gyeonggi Province, Wednesday, over his declaration of martial law. Newsis

The Corruption Investigation Office for High-ranking Officials (CIO) requestd a Seoul court to issue an arrest warrant for President Yoon Suk Yeol on Friday over his decision to impose martial law on Dec. 3.

This comes several hours after the impeached leader refused further questioning by the CIO. Yoon has declined to cooperate with the investigation after undergoing more than 10 hours of questioning on Wednesday, the day he became the first sitting president of Korea to be detained.

The CIO asked the Seoul Western District Court to approve the arrest warrant for Yoon on charges of leading an insurrection, a crime punishable by death or life in prison. The court is the same one that previously issued a warrant to detain Yoon at the corruption investigation agency's request.

"The severity of the crime and the risk of recidivism were factored in [the decision to seek a warrant]," a CIO official told reporters. "It was sent [to the court] at 5:50 p.m. The charges included were leading an insurrection and abuse of power."

If approved, investigators will be given 20 more days to keep him in detention, during which they will finalize an indictment against him.

Judge Cha Eun-kyung will hold a hearing on the warrant at 2 p.m. on Saturday.

Yoon's defense team did not immediately comment on the CIO's decision. Instead, it released a statement in which the president expressed his gratitude to his supporters.

"It's a bit uncomfortable here, but I have been doing well in this detention center," the statement said. "I was told that many people came out to the streets to support me and the nation despite the cold weather ... I want to thank everyone for showing patriotism."

The CIO, leading a joint investigation with the police and the defense ministry, has alleged that Yoon committed at least two serious criminal offenses ― insurrection and abuse of power ― by authorizing and implementing the martial law order.

Yoon's lawyers contend that the CIO lacks the legal authority to investigate accusations of insurrection. They cite a law explicitly designating the police as the sole authority to handle such matters. For this reason, they claimed the detention warrant requested by the CIO was flawed in the first place.

But the CIO maintains its investigative jurisdiction, stating that insurrection can constitute "a crime related" to abuse of power, a charge clearly within its authority.

Judge So Joon-sub at the Seoul Central District Court ruled in favor of the CIO, saying there was no violation of law during the agency's legal process to obtain the warrant to detain the president.

During the CIO's interrogation, Yoon largely remained silent, according to investigators. But the prosecution has reportedly secured more than 1,400 pages of investigation documents, in which Yoon's alleged rebellion accomplices, including Army Chief of Staff Gen. Park An-su and Defense Counterintelligence Command chief Yeo In-hyung, said what the commander-in-chief allegedly instructed them to do to implement martial law.

What is written in the documents as well as Yoon's refusal of cooperating with the efforts to investigate the case would likely be factored in a court decision over whether the president should be formally arrested.

Article 70 of the Criminal Procedure Act states that an arrest warrant can be issued for a suspect if the person "has no fixed dwelling" or if there are reasonable grounds to suspect that the person "may destroy evidence" or "flee."

But other factors, such as his status as a sitting president, could also affect the decision.

Yoo Chang-hoon, a judge at the Seoul Central District Court, dismissed an arrest warrant four months ago for Lee Jae-myung, leader of the Democratic Party of Korea, who was accused of persuading someone to commit perjury. Yoo stated that there was little risk of evidence destruction, considering Lee's "status as a sitting chairman of a political party."

The CIO plans to spend 10 more days to back up its case against Yoon before handing the case over to prosecutors, as the two agencies agreed previously.

The same day, the police detained Kim Seong-hoon, acting head of the Presidential Security Service, over allegations that he played a key role in hindering the execution of a warrant to detain the president on Jan. 3. Before he was taken into custody, Kim told reporters outside the police building that he had carried out "legitimate security duties."