The Corruption Investigation Office for High-Ranking Officials is leading a joint investigation with police and military authorities on Yoon’s ill-conceived power grab that lasted only several hours.

South Korean police have questioned Prime Minister and Acting President Han Duck-soo as part of an investigation into the short-lived decision this month to impose martial law, an official at his office said on Friday.

Some members of President Yoon Suk Yeol’s own party helped remove him from office. But the political uncertainty is far from over.