The special counsel team investigating allegations against former first lady Kim Keon-hee has questioned a former BMW dealer chairman as part of its probe into alleged stock price manipulation involving Kim.

Kwon Oh-soo, former chairman of Deutsch Motors, a BMW dealership in South Korea, appeared at special counsel Min Joong-ki's office in central Seoul on Sunday morning.

Kwon entered the building without responding to reporters who asked whether he intended to fully cooperate with the investigation.

In April, the Supreme Court convicted Kwon of violating the Capital Markets Act, sentencing him to three years in prison with a four-year suspension and imposing a fine of 500 million won.

Kwon and other accomplices allegedly inflated Deutsch Motors' stock price between 2009 and 2012 to secure illicit profits.

Although the former first lady was suspected of involvement, prosecutors ultimately did not indict her.