A South Korean court has sentenced the operator of a vast online sex trafficking ring to 40 years in prison in a case that outraged the nation. Cho Ju-bin, 25, oversaw a group of 38 accomplices who befriended and then blackmailed at least 74 women into sharing explicit videos that were then posted in pay-per-view internet chat rooms. Sixteen of the victims were less than 16 years old, the age of consent in South Korea. The Seoul Central District Court on Thursday found Cho guilty of violating laws to protect minors from sexual abuse and of making a profit from producing and selling abusive footage, Yonhap News reported. Indicted on 14 criminal charges, including inducing another person involved in the trafficking ring to rape a teenage girl and concealing more than £70,000 in criminal proceeds, prosecutors had initially demanded a life sentence on the grounds of the “irreperable damage” Cho had caused his victims. They had also requested that he be obliged to wear an electronic monitoring device for 45 years. In a petition to the court, one of the women said Cho, who had worked in an orphanage and adopted the online name “The Doctor”, was “evil” and deserved a 2,000-year prison term. Passing sentence, the judge said: “The accused has widely distributed sexually abusive content that he created by luring and threatening many victims.” Media reports have suggested that some of the video clips showed a group of men raping a teenage girl in a motel room, while others included images of the word “slave” cut into a woman’s body. One video showed girls “barking like dogs”, the Kookmin Ilbo newspaper reported. Cho operated the chat room on the Telegram messenger service, with at least 10,000 people accessing the site and paying as much as £1,000 for access. Authorities have been tracing people who used the site and have identified serving police officers and teachers as among the users. Cho’s arrest in March sparked fury across South Korea after prosecutors initially refused to name the suspect before his trial opened. Within days, more than 5 million people had signed petitions on the home page of Moon Jae-in, the South Korean president, demanding that the authorities withdraw his right to anonymity. A committee of senior judicial officials, a psychologist and a psychiatrist weighed the public’s right to know and took the unprecedented step of naming Cho. He was then brought out in handcuffs from a police station in central Seoul to face the public. “I apologise to those that I hurt”, Cho said. “Thank you for putting a brake on the life of a devil who could not be stopped.” South Korea’s Ministry of Justice has been the target of criticism for its failure to deal with the growing use of technology to carry out sex crimes, with one ministry official admitting that the case had been “a disaster” and apologising for its “lukewarm response” to online sexual abuse cases.