South Korea’s impeached President Yoon Suk Yeol appeared in court Tuesday for hearings that will determine whether he is officially removed from office following his controversial declaration of martial law.

Yoon, a former prosecutor, threw the country into political turmoil on December 3 by imposing martial law, suspending civilian rule, and deploying soldiers to parliament. The opposition-led legislature defied military intervention, voted down the decree, and swiftly impeached him.

In January, authorities arrested Yoon on insurrection charges, making him the first sitting South Korean president to be detained. He remains in custody but has been attending impeachment hearings at the Constitutional Court, which will decide whether his removal stands. If upheld, a new election must be held within 60 days.

During Tuesday’s session, former military officials and an ex-intelligence officer testified, with one contradicting Yoon’s denial of ordering arrests of politicians. Prosecutors have labeled him the “ringleader of the insurrection,” and he faces a separate criminal trial that could lead to imprisonment or the death penalty.