The local political fund law bans a registered firm or group from donating any funds to lawmakers. Donations made with company money is also forbidden.

Police have carried out raids at KT headquarters and its affiliates based on evidence that KT executives bought large amounts of gift vouchers with company funds and cashed them out for donations.

Police believe that the donations were given to lawmakers who had belonged to the parliamentary committee in charge of telecommunications, in return for legislations and policies favorable to the Internet-only banking service, KT's newest business.

"Depending on his statements, it is possible there will be a second interrogation (of Hwang)," an official said.

Hwang took the helm of the mobile carrier in 2014 and renewed his term for another three years last year. The former Samsung Electronics executive is best known for his pioneering work in the development of memory chips. (Yonhap)