Prosecutors on Friday are set to indict a former mayor of Busan, South Korea's largest port city, who is suspected of receiving bribes while he worked at the state financial regulator.

An official at the Seoul Eastern District Prosecutors Office said prosecutors plan to indict Yoo Jae-soo, who recently resigned as vice mayor of economic affairs in the southeastern city. 

Yoo, 55, is accused of receiving bribes worth a combined 50 million won ($43,000) from three to four financial firms during his term at the Financial Services Commission. He is also suspected of asking a financial asset firm to hire his sibling and pay wages of at least 100 million won.

Prosecutors are also looking into why the presidential office's special inspection into Yoo's case was abruptly suspended.

The former mayor was under surveillance by a special inspection team of Cheong Wa Dae over allegations that he took bribes from businesses when he served as an FSC director-general.

Yoo, however, avoided punishment for an unknown reason and became Busan's vice mayor in 2018.

Prosecutors have called in officials who are allegedly involved in or are seen to have knowledge of an alleged cover-up of the bribery case.

Earlier this month, prosecutors also executed a court-issued search warrant at Cheong Wa Dae in connection with the ongoing probe.

The raid appeared to zero in on former Justice Minister Cho Kuk, the former top presidential secretary for civil affairs who is under a separate prosecution probe over family-related allegations.

Cheong Wa Dae spokesperson Ko Min-jung said the presidential office "faithfully cooperated" with the relevant procedures and submitted some documents and materials in consultation with the prosecution. (Yonhap)