The woman at the center of a deepening political crisis around South Korean President Park Geun-hye will cooperate with prosecutors investigating allegations that she had improper control over state affairs, her lawyer said on Sunday.
Choi Soon-sil returned to South Korea early on Sunday from Germany, where she had been staying, her lawyer told reporters.
"Choi has expressed through her attorney that she will actively respond to prosecutors' investigation and will testify according to the facts," Lee Kyung-jae, her lawyer, said on Sunday morning.
"She is deeply remorseful that she had caused frustration and despondency among the public," Lee said.
Choi left Europe on a flight from London to avoid media camped out in Germany, Lee said. She would make herself available for questioning by prosecutors, he said.
In the midst of the political crisis, Park has accepted the resignations of five of the top presidential aides, including the chief of staff, the presidential office said on Sunday.
Three long-time Park aides, the insular core of advisers who have been criticized of tightly controlling the access to the president, had also stepped down, according to the presidential office.
Park's office said on Friday she ordered her senior secretaries to tender their resignations.
Choi was under intense pressure to return to South Korea as the political crisis engulfed Park over allegations that she allowed Choi to use her friendship to exert improper influence and benefit personally.