EXPLAINER: What you need to know about trials faced by South Korea's former President Yoon

A South Korean court on Thursday sentenced former president Yoon Suk Yeol to life in prison for leading an insurrection when he made a short-lived martial law declaration in December 2024.

Yoon, a former top prosecutor before becoming president, faces eight separate trial proceedings concerning his martial law declaration in 2024 and other actions, having lost presidential immunity since he was ousted by the Constitutional Court in April last year.

Here is what we know about Yoon's criminal trials:

INSURRECTION TRIAL

The Seoul Central District Court handed Yoon a life sentence on charges of masterminding an insurrection when Yoon declared the surprise martial law in December 2024.

Prosecutors had sought the death penalty, arguing that he lacked the legal grounds at the time to declare martial law and order troops to arrest lawmakers.

South Korea last handed down a death sentence in 2016, but has not executed anyone since 1997.

Yoon has denied the charges and said that his martial law declaration, which lasted about six hours, was to protect liberal democracy.

Yoon, who has been detained at the Seoul Detention Centre, is expected to go back to his cell due to the ruling. His lawyer said they will discuss an appeal.

The lower court also handed down a 30-year jail sentence on Yoon's former defence minister, Kim Yong-hyun, for alleged insurrection and abuse of power. Prosecutors had sought a life sentence.

Former senior police officials were also handed jail sentences.

MARTIAL LAW CHARGES

On January 15, 2025, Yoon became the first sitting president to be arrested after a lengthy showdown with law enforcement officials.

He was released from jail on March 8 after a court cancelled his arrest warrant, citing the timing of the indictment and questions about the legality of the investigation.

But the former leader returned to detention on July 10, after the court granted a detention warrant requested by a special prosecution team investigating additional charges.

Yoon had already received a five-year jail term in January in a separate trial for charges that included obstructing attempts by authorities to arrest him by deploying presidential security service officials.

Yoon, who has denied the charges, has appealed.

The special counsel team created after new President Lee Jae Myung took office in June also accused Yoon of trying to provoke North Korea into mounting an armed aggression to justify his martial law declaration and eliminate political opponents.

OTHER CHARGES

Yoon also faces trials on charges including perjury concerning his testimony during a trial involving his former prime minister, and a violation of the Political Funds Act related to a power broker associated with his wife and former first lady Kim Keon Hee.

In addition, Yoon has been charged with abuse of authority and obstruction of exercise of due rights over allegations that military officials and the presidential office interfered in an internal investigation into the death of a marine in 2023.

Yoon has denied these charges.

-Joyce Lee/Reuters