SEOUL, South Korea (AP) — South Korean anti-corruption agency said Tuesday that a court has issued a warrant to detain impeached President Yoon Suk Yeol.

The Corruption Investigation Office for High-Ranking Officials said in a statement that the Seoul Western District Court issued a warrant to detain Yoon over his stunning yet short-lived martial law decree earlier this month.

The agency said it is investigating whether his declaration of martial law amounted to rebellion.

Yoon’s powers have been suspended since the opposition-controlled National Assembly voted to impeach him on Dec. 14. The Constitutional Court is to determine whether to dismiss Yoon as president or reinstate him.

But he has since ignored repeated requests by investigative authorities to appear for questioning and allow them to search his office.

Yoon has the presidential privilege of immunity from criminal prosecution, but it does not extend to allegations of rebellion or treason.