The man central to blocking investigators from arresting South Korea's impeached President Yoon Suk Yeol has come under the spotlight himself in the political crisis sparked by Yoon's brief declaration of martial law last month.

South Korea’s anti-corruption agency was unable to bring Yoon to custody following a standoff with the security service of the suspended president last week.

Blocked by bodyguards, officials retreated after several hours without serving a court warrant to hold President Yoon Suk Yeol for questioning on insurrection charges.