Prosecutors are looking into various allegations surrounding a former associate of ousted President Park Geun-hye's close friend, who made key testimonies in relation to an influence-peddling scandal that resulted in Park's removal from office, sources said Wednesday.

Prosecutors questioned Ko Young-tae, who used to be Choi Soon-sil's close associate, on Tuesday over a number of complaints filed against him.

Ko, who made some clothing items and bags for the former president, made public controversial relations between Park and Choi last year. Ko claimed that Choi received and edited the former president's speeches in advance.

While he was hailed by some as a whistle blower, some raised suspicions that he made the disclosure to gain control of a company owned by Choi.

Choi, currently standing trial over a string of corruption allegations, is accused of attempting to pocket profits through the firm based on her ties to the former president.

Prosecutors declined to confirm on what charges they are investigating Ko. (Yonhap)