SEOUL (Diya TV) — South Korea’s suspended President Yoon Suk Yeol was arrested Wednesday as part of an anti-graft agency investigation into alleged insurrection, making him the first sitting president in the nation’s history to face arrest.

The Corruption Investigation Office for High-ranking Officials, leading the investigation into Yoon’s role in declaring martial law on December 3, is essentially an independent agency launched in 2021 to investigate senior officials. That agency cannot prosecute presidents directly and must refer cases to the prosecutors’ office to become a matter of prosecution.

Yoon was taken to the CIO offices in Gwacheon, just outside Seoul, where he is being questioned. The investigators have prepared a 200-page questionnaire for him, although questioning will not be video recorded at his request, according to a CIO official.

While in detention, Yoon will be kept in a solitary cell at the Seoul Detention Centre in Uiwang, 22 kilometers south of the capital. The authorities will decide within 48 hours whether to seek a formal detention warrant that would allow him to be detained for up to 20 days or release him.

The probe has brought to the fore concerns over the CIO’s ability to handle such a massive case, considering that the agency currently operates with a skeleton staff. The prosecution team, headed by CIO chief Oh Dong-woon, consists of only nine prosecutors.

Yoon’s arrest is not the first instance of South Korean leaders facing legal woes. Former President Park Geun-hye and Samsung Electronics Chairman Jay Y. Lee have also been detained at the Seoul Detention Centre.

The detention center said Yoon’s meals would meet the standard 2,500-calorie menu, costing about 1,600 won ($1.09) per meal, including dishes like bean sprout soup and kimchi.