South Korea’s intelligence agency confirmed that North Korea executed Defense Minister Hyon Yong-Chol on April 30 for reportedly falling asleep during a military parade attended by Supreme Leader Kim Jong-Un and talking back to Kim Jong-Un. Hyon was executed using large-caliber anti-aircraft guns, a gruesome execution reportedly reserved for high-ranking North Koreans who fall out of favor with the country’s tyrannical leadership.

Hyon was charged with treason, according to the South Korean National Intelligence Service, which keeps an unblinking eye on changes in key leadership positions north of the border. Hyon himself was reportedly promoted to the position of Minister of the People’s Armed Forces after his predecessor was purged by Kim in 2013. He was the fourth person to hold the position since Kim came to power in 2011 following the death of his father, Kim Jong-Il, according to the Center for Strategic and International Studies. North Korea's KCNA official news service has not publicly announced Hyon's execution.

The roughly 60-something-year-old Hyon reportedly joined the military in 1966, became a general in 2010, but only became a politically notable figure in the military when the third Kim took over the hermit kingdom. He was made vice marshal in early 2012 and chief of the General Staff of the Korean People’s Army by June of that year. He saw his fair share of demotions, promotions and shufflings over the last four years as Kim either executed or made irrelevant hundreds of top North Korean officials and their supporters in numerous mass purges in attempts to consolidate power.

Kim’s brutal style of leadership is unsustainable, said one defector in an interview with CNN this week, who predicted that Kim will fall out of power within three years if he keeps his pace up. Kim has ordered the executions of 15 officials this year alone, but it was the execution of Kim’s own uncle-in-law Jang Sung-taek in 2013 that brought international attention to the 32-year-old’s brutality. Jang was a high-ranking official in North Korea who was close to Kim’s father and reportedly a mentor figure to the younger Kim. Jang too was found guilty of treason.