The leader of a high-profile digital sexual exploitation ring was indicted and referred for court trial Monday for allegedly producing and distributing sexual exploitation materials online for profits, prosecutors said.

Cho Ju-bin is accused of blackmailing female victims, including underage girls, into providing their sexual videos from last May to February, which were then posted in his pay-to-view chat room, dubbed "Baksabang," meaning doctor's room in Korean, on the Telegram messenger service, according to the Seoul Central District Prosecutors Office.

At least 25 people, including eight underage girls, have been confirmed to be exploited by Cho, the prosecution said.

Cho allegedly had a co-conspirator attempt to sexually assault a 15-year-old girl last October after threatening to disclose her nude photo. The suspect allegedly made similar threats to three other victims last year, prosecutors said, noting he will face a total of 14 criminal charges, including violation of the Act on the Protection of Children and Youth against Sex Offenses.

The 24-year-old man is suspected of selling abusive sexual materials obtained from his victims through blackmail to Baksabang's paid members, estimated to reach 15,000, in exchange for cryptocurrencies.

The prosecution requested a seizure of Cho's 15 cryptocurrency wallets and securities deposits and stocks, as well as a preservation of 130 million won ($106,700) in cash confiscated from him.

In addition, Cho was charged with defrauding a freelance journalist of 15 million won by falsely promising to offer information on renowned figures.

Cho allegedly enlisted the aid of three main accomplices in the operations of the Baksabang chat room and two of them have been arrested, with another remaining at large.

Local courts have issued pretrial detention warrants for the two accomplices -- an Army soldier and an 18-year-old man -- on charges of having recruited and managed Baksabang's paid members and delivering criminal proceeds from the chat room to Cho.

A former public service worker was also arrested April 3 for allegedly making illegal inquiries into personal information of hundreds of people and leaking that information to Cho.

Prosecutors said they will conduct further investigations into Cho and his accomplices before deciding whether to apply the charge of organization of a criminal group to them.

Prosecutors also called for a legal revision to mandate the public disclosure of the personal identities of all criminals convicted of sexual crimes against minors younger than 13.

Meanwhile, the Seoul Metropolitan Police Agency said it has so far booked 30 paid members of Baksabang for possessing child sexual exploitation materials and other charges and will further expand its investigations into other paid members.

The police agency also said it will push for the disclosure of the personal information of Cho's accomplices, including the 18-year-old man surnamed Kang.

Police have obtained the nicknames of about 15,000 paid members of Baksabang from digital data secured from Cho and are now tracking down their personal identity information.

A man in his 40s took his own life in Seoul last month after leaving a suicide note in which he said he regrets paying money to Baksabang and feels sorry for the victims. (Yonhap)