The former head of a major South Korean entertainment and media firm has been questioned by police on allegations that he provided sexual services to investors from Southeast Asia.

The Seoul Metropolitan Police Agency called in former YG Entertainment CEO Yang Hyun-suk at 4 p.m. Wednesday and questioned him for nine hours. 

Yang is suspected of extracting favors from the investors by inviting some ten prostitutes to a meeting with them at a high-end restaurant in Seoul in July 2014. At least some of them are expected to have engaged in sexual activities with the investors.

Yang has denied the allegations, saying that he had met with the investors at the restaurant but he did not offer sex in exchange for favors. 

K-pop star Psy, who reportedly introduced the investors to Yang and was present at the dinner, was also summoned and questioned as a witness last week.