Special counsel Min Joong-ki, who is leading investigations into former first lady Kim Keon-hee, has denied accusations that he was involved in insider trading.

In a statement released Monday, Min apologized that his personal trading had caused controversy but claimed he had not violated any laws and had not used undisclosed information in the process of buying and selling stocks.

Min has come under scrutiny for selling unlisted shares of Neo Semi-Tech, a solar energy company, back in 2010, when he was a senior judge, and earning around 100 million won.

He sold the shares just before the company was delisted due to accounting fraud.

Min and Oh Myung-hwan, the former CEO of Neo Semi-Tech, both attended Daejeon High School and Seoul National University, raising further suspicions. Oh also sold his shares of the company around the same time that Min did.

Min's special counsel looked into Neo Semi-Tech while investigating Kim’s alleged involvement in the Deutsch Motors stock price manipulation case. Kim had talked about the solar company’s shares in a phone call with an employee of a securities firm in 2009.

The special counsel team determined that Kim had a strong understanding of the stock market based on her mention of Neo Semi-Tech and other stocks deemed difficult for novice investors to access.

However, this information was not included in their indictment.