According to the police, Ms. Yoon and others were paid about 100,000,000 won since August 2007 for the smuggling of drugs such as ecstasy and ketamine. It was discovered during the investigation that Ms. Yoon would hide the drugs in her underclothes after obtaining them in Japan. The drugs would then travel through different people and Mr. Yeh, who happened to be the 3rd point of transfer. His drugs were then sold throughout clubs in Kang Nam and to his acquaintances.
Joo Ji Hoon began to associate himself with the two around March 2008 and has been charged by the police, for being involved in the 2nd point of transfer of the drugs. A police representative stated, "This is the first time that celebrities are directly involved in the buying and selling of drugs. We are expanding the scope of our investigations and expect to discover more people selling the drugs beneath the sponsor.