Special counsel Min Joong-ki’s team summoned first lady Kim Keon-hee on Monday for a second round of questioning since she was placed in detention last week.
Prosecutors said the morning session focused on allegations of political nomination and election interference, during which Kim largely exercised her right to remain silent, occasionally responding that she did not know or could not remember.
The afternoon session was set to address stock manipulation allegations involving Deutsch Motors.
Kim was taken into custody on Tuesday last week and has already been questioned once, with investigators looking at how she obtained polling data from a political broker free of charge.
The special counsel also announced the indictment of two men in custody in connection with a bribery case linked to Kim and shaman Geon Jin, including a former Unification Church executive accused of delivering luxury gifts to her in 2022 in exchange for favors.
He additionally faces charges of funneling illicit political funds, while an associate is accused of accepting bribes in return for arranging to influence public officials.