A Seoul court on Thursday sentenced the mastermind of one of the country's largest online sex trafficking rings to 40 years in prison.

The Seoul Central District Court found Cho Ju-bin guilty of violating laws to protect minors from sexual abuse and of operating a criminal ring to make profits by producing and selling abusive videos.

The court also ordered to make public his personal details for 10 years and ban him from working at children-related facilities for 10 years after his release. Cho also has to wear an electronic bracelet for 30 years and pay a forfeiture of 100 million won ($90,000).

"The accused has widely distributed sexually abusive content that he created by luring and threatening many victims," the court said, adding that Cho caused his victims irreversible damage by releasing their private information.

The court said Cho should be removed from society for a long time, given "the gravity of his crimes, the sheer number of victims and damage done to them, his evil influence on society and his (unrepentant) attitude."

Earlier this year, the online predator was indicted on 14 counts of criminal allegations. Cho was accused of organizing a criminal ring from last May to February this year, during which he and his accomplices blackmailed 74 women, including 16 minors, into filming sexually abusive content and selling them to the members of Baksabang, an online chat room on Telegram.

The 25-year-old college graduate was also alleged to have ordered one of his conspirators to rape an underage girl after blackmailing her over her nude video.

The court also sentenced four of Cho's accomplices to seven to 15 years in prison, and a maximum of 10 years in imprisonment for a 16-year-old accomplice who is subject to the Juvenile Act, for working for the online sex abuse ring.

The punishment fell short of a life sentence sought by prosecutors last month who cited irreparable damage done to his victims. One of the victims said in a petition that Cho and his co-conspirators are evil and deserve imprisonment for 2,000 years.

Calling the ruling "only the start to the end of the Telegram sex abuse case," civic groups urged law enforcement and the judiciary to work toward protecting the rights of sex abuse victims.

At a press conference held after the rulings were made, Cho Eun-ho, a lawyer from Minbyun, a social group of progressive lawyers, said, "Law enforcement and the court should use every possible means to protect the rights of victims, who can be empowered to live their lives again by helping bring the perpetrators to justice." (Yonhap)