An Jong-beom, former secretary to South Korean President Park Geun-hye, was summoned by prosecutors on Wednesday for his alleged involvement in a scandal.
The scandal surrounds Choi Soon-sil, a longtime confidante of the president suspected of intervening in state affairs.
An Jong-beom, former presidential secretary on policy coordination, appeared at about 1:50 p.m. local time in the headquarters of the Seoul Central District Prosecutors' Office in charge of probing the Choi Soon-sil case.
An, who stepped down on Sunday, is suspected of being involved in pressuring conglomerates, including Samsung and Hyundai, into donating tens of millions of U.S. dollars to nonprofit Mir and K-Sports foundations allegedly controlled by Choi.
The former presidential advisor has denied his involvement, but multiple people engaging in the donations have told prosecutors and media outlets that An has played a role in the fundraising of the foundations.
Before entering the prosecutors' building, An told reporters that he will take responsibility if there is any wrongdoing confirmed.
Choi is being grilled by prosecutors for a third day after being placed under an emergency arrest on Monday night. The prosecution plans to request a warrant to formally detain her on Wednesday.