South Korean police are formally building a case against impeached President Yoon Suk Yeol over accusations he obstructed the execution of an arrest warrant, a police spokesperson said on Friday. A South Korean court issued an arrest warrant for Yoon on December 31 in a criminal investigation accusing the suspended leader of insurrection over his martial law decree last year.

South Korea’s impeached President Yoon Suk Yeol appeared in a Seoul court on Thursday for his first trial hearing on charges of insurrection in the country’s first criminal prosecution of an incumbent leader.

South Korean President Yoon Suk Yeol contested his arrest on rebellion charges in one court and pleaded to preserve his presidency in the other, both cases related to his brief imposition of martial law.