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.

The president faces an accusation of insurrection and, in a first for a sitting leader, the possibility of arrest. Here’s what to know about his political future.