A court has rejected President Yoon Suk-yeol’s appeal challenging his arrest on charges of orchestrating insurrection, extending his detention and resuming the 48-hour limit for his arrest warrant.

The Seoul Central District Court dismissed Yoon’s request late on Jan. 16, around 11 p.m., stating the “appeal lacks sufficient grounds.” Yoon’s legal team had argued that his arrest by the Corruption Investigation Office for High-ranking Officials (CIO) was unconstitutional but failed to convince the court.

On the same day, Yoon, in his second day of detention, declined to attend a scheduled round of questioning by the CIO, citing health concerns and reiterating his stance. “The president has already clarified his position and sees no need for further questioning,” said his attorney, Yoon Kab-keun, adding that the defense plans to submit a written statement addressing the charges.

The CIO arrested Yoon on Jan. 15 on allegations of leading an insurrection. After a 10-hour interrogation, during which Yoon refused to answer questions, he filed the now-rejected appeal.

President Yoon Suk-yeol, following his investigation by the Corruption Investigation Office for High-ranking Officials (CIO) on the evening of Jan. 15, is seen traveling to the Seoul Detention Center in a Presidential Security Service vehicle. Yoon was detained in the facility’s "detainee waiting room." The CIO questioned Yoon for 10 hours and 40 minutes, from 11 a.m. to 9:40 p.m., during which he reportedly exercised his right to remain silent and did not respond to the investigators' questions./Chang Lian-cherng

The court’s decision means Yoon will remain at the Seoul Detention Center while the CIO determines whether to seek an arrest warrant, a decision expected as early as Jan. 17.

Meanwhile, the Constitutional Court formally began impeachment proceedings against Yoon on Jan. 16. His legal team responded by filing criminal complaints against CIO Chief Oh Dong-woon and National Police Agency Chief Woo Jong-soo, accusing them of insurrection related to the investigation.

Reports from the detention center indicate that Yoon spent his first night in custody wearing a shirt and trousers instead of the standard-issue prison uniform. He reportedly struggled to sleep and ate only half of his breakfast of cereal, boiled eggs, nuts, and milk.

Yoon is being held in a 200-square-foot detainee room equipped with basic amenities, including a small table, a television, and a private restroom.