A former member of South Korean boy band FT Island, Choi Jong-hoon, has filed a complaint with the prosecution against a woman suspected of blackmailing him, police said Thursday.

The Seongdong Police Station said it launched an investigation into the case last Friday under direction from the Seoul Eastern Prosecutors' Office.

The revelation came the same day a report emerged that Choi is suspected to have sexually assaulted the woman, whose name was withheld, in March 2012 in the United States by having her take what is known as a date rape drug.

A lawyer representing Choi said the performer admitted to meeting her in the US but denied raping her, adding Choi believes the woman appeared to be blackmailing him at a time when he has been engulfed in a snowballing sex video scandal.

Choi has undergone police questioning over allegations he received and watched illegal video footage uploaded by Jung Joon-young, who is at the center of the scandal, through the mobile chat messenger KakaoTalk. Seungri, a former member of K-pop boy band BIGBANG, Yong Jun-hyung of Highlight and Lee Jong-hyun of CNBLUE are known to have been members of the group chat.

Choi is also accused of having asked a high-ranking police official to use his influence to prevent newspapers from covering his drunk driving incident three years ago. He has denied the accusation.

The 29-year old was kicked out of his boy band right after his involvement surfaced, while Seungri and Yong Jun-hyung have faced similar fates.

The scandal has put the local entertainment industry under fire, drawing criticism from a public dismayed at the news and creating a swirl of rumors and speculation about who the women in Jung's videos might be. (Yonhap)