South Korea’s impeached president, Yoon Suk Yeol, has been arrested and is being questioned over his ill-fated declaration of martial law last month, anti-corruption investigators said on Wednesday, bringing to an end an early-morning standoff outside his official residence in Seoul. His detention makes him the first sitting president in the nation’s history to be arrested. CIO officials said Yoon was refusing to talk during questioning but did not give further details as to why he remained silent. Yoon said in a video message released before his arrest that he had agreed to cooperate with anti-corruption authorities to “avoid bloodshed”