The Corruption Investigation Office for High-ranking Officials(CIO) has summoned a prosecutor with suspected links to a political meddling scandal involving former Prosecutor-General Yoon Seok-youl.

Son Jun-sung is being questioned for allegedly ordering prosecutors to file complaints against pro-government figures ahead of last year's general elections, and conspiring with PPP Rep. Kim Woong to lodge the defamation complaints.

It is the first summons of a suspect since the CIO began its probe in September. It had requested an arrest warrant for Son last month but was rejected on insufficient grounds. 

Whether the investigative office has seized new evidence since then will likely be the key in the latest questioning. The CIO is also reportedly planning to question Kim Woong on Wednesday.