Yoon Suk Yeol, who became the first sitting South Korean president to be arrested Wednesday, has not attended a second day of questioning about his bid to impose martial law.
Yoon was held at the Seoul Detention Center on Thursday after refusing to cooperate, with his lawyer citing his health as a factor for his absence from the questioning.
The court held the second hearing in his impeachment trial to determine whether to remove Yoon permanently or reinstate his presidential powers.
He faces charges of insurrection with his martial law order. On Wednesday, he was questioned for hours, but exercised his right to remain silent before being moved to a detention center.
On Wednesday, hundreds of police and investigators bypassed bus barricades, cut barbed wire and scaled ladders to get inside the compound where Yoon was staying to arrest him.
He said he complied with investigators to avoid "bloodshed" but did not accept the legality of the investigation.
Yoon shocked the nation on December 3 when he declared martial law, claiming he needed to safeguard South Korea "from the threats posed by North Korea's communist forces and eliminate anti-state elements".
His lawyers claim an arrest warrant for a sitting president, who has total immunity, is “an illegal, invalid warrant.” The suspended president’s backers have also insisted that the actions being taken against the sitting president contradict South Korean law.
The current arrest warrant allows investigators to hold Yoon for up to 48 hours. Officials would need to apply for a new arrest warrant to keep him in detention after Friday.