Prosecutors on Thursday demanded a life sentence for the mastermind of one of the nation's largest online sex trafficking rings, saying his victims have made tearful pleas for that he be sternly punished.

Prosecutors also asked the court to order Cho Ju-bin, a 24-year-old indicted for blackmailing women and girls into providing sexual videos and photos to a pay-to-view Telegram chat room, to wear an electronic monitoring device for 45 years during a hearing at the Seoul Central District Court.

Prosecutors sought prison sentences of 10 to 15 years for four of Cho's accomplices and a 10-year imprisonment for a 16-year-old accomplice and asked the court to ban them from working with children and youths and at welfare facilities for the disabled and wear electronic bracelets.

Cho's victims have submitted written petitions to the court through their lawyers, saying their damage will never be forgotten and Cho and his accomplices must be strongly punished. One of the victims said in a petition that Cho and his co-conspirators are evil and deserve imprisonment for 2,000 years.

Delivering a final statement during the hearing, Cho said he has regrets about failing to respect human dignity and wants to sincerely repent for his offenses. Cho's accomplices also expressed remorse for their crimes but one of them, surnamed Kang, refused to offer an apology.

The sentencing hearing is slated for Nov. 26.

The prosecutors' demand came one day after they additionally indicted Cho and one of his accomplices for concealing criminal proceeds.

Cho was additionally charged with hiding about 108 million won ($95,200) in criminal proceeds on 53 occasions, according to the Seoul Central District Prosecutors Office.

One of Cho's accomplices, identified only as Kang, was also additionally accused of changing 3.5 million won of cryptocurrency earned from the Telegram chat room called Baksabang, Korean for doctor's room, into cash and delivering the money to Cho, the office said.

Cho was earlier indicted for organizing a criminal ring together with 38 accomplices, blackmailing 74 minor and adult victims into filming pornographic content and distributing the sex abuse materials to Baksabang members.

Prosecutors asked the court to merge the additional charges against Cho and Kang into their ongoing trials. They have been expanding their probe into Baksabang and other illegal Telegram chat rooms to punish their members. (Yonhap)