The court issued a warrant for Kim, Kyunghyang reported; investigators suspect he crafted justifying logic for the decree and took part in its execution.

The special counsel the same day sought a warrant for Lee Si-won, a former presidential discipline secretary, over alleged pressure on the Corporal Chae probe, widening the net.

With a key figure in custody, momentum is building in political circles to extend the counsel's investigation period.

Further judicial action against the decision-making line around the decree could follow, a major variable for the second half's politics.

For foreign and overseas-Chinese communities, the trajectory of Korea's political-legal risk bears watching for its effect on the won and investor sentiment.