Yoon Suk Yeol, South Korea’s since-impeached president, had been planning for months to impose martial law and target political opponents, according to accounts.

South Korea’s President Yoon Suk Yeol again declined to appear for questioning by investigators over his martial law declaration as the embattled leader seeks to first defend himself at an impeachment trial.

South Korean investigators on Friday pressed ahead with their probe into impeached President Yoon Suk Yeol over his Dec. 3 martial law declaration, issuing another summons demanding that he appear for questioning on Christmas Day,