SEOUL — South Korean police took the rare step of identifying and parading the suspected leader of a sexual blackmail ring in front of the press and protesters on Wednesday, after the case triggered a national uproar.

The police asked prosecutors on Wednesday to indict 24-year-old Cho Joo-bin for allegedly blackmailing at least 74 women, including 16 minors, into producing sexually degrading videos of themselves, and then posting in pay-to-view chat rooms.

The allegations prompted a national outcry in South Korea over a growing spate of online postings of illegal sexual images obtained through blackmail or filmed secretly — a practice that critics say is aggravated by a lack of respect for women, weak laws and penalties.

More than 1.8 million people signed a petition asking the presidential Blue House to release the identities of members of a group-chat network where the videos had been posted. Local media said the network had 260,000 people, but police said some were double-counted and that others were not paying members.

Another petition calling for the main suspect to be publicly paraded in a perp walk attracted more than 2.5 million signatories since his arrest last week. The National Police Agency said it decided to publicly release Cho’s identity in hopes of deterring similar offenses. It cited “his malicious and repetitive criminal method that forced sexually abusive videos out of women whom he labeled slaves.”

“We decided to release his name, age and face after reviewing how it would serve the public interest regarding the people’s right to know and the prevention of similar crimes from recurring,” the agency said Tuesday.

Law enforcement authorities in South Korea usually refrain from personally identifying suspects on grounds of privacy rights and possible impacts on their family members.

Cho appeared in handcuffs Wednesday outside a Seoul police office, where he was faced by a swarm of reporters and protesters before being transported to the prosecutor’s office.

“Thank you for stopping the life of a demon that could not stop,” Cho said as he was escorted away as cameras flashed and protesters shouted. He apologized to “all the people who have been hurt by me,” but he did not answer questions about the accusations he is facing.

Cho is accused of luring the women through fake ads for high-paying jobs and then blackmailing them into sending sexual images of themselves, local media reported, citing police.

He had allegedly obtained personal information on the women with help from workers at local government offices, then used the information to threaten the women into filming sexually degrading images of themselves, local media reported.

President Moon Jae-in on Monday ordered a thorough investigation of all operators and members of the chat-room network, calling it a “cruelty that destroys a person’s life.”

Under the alias “Doctor,” Cho posted the images of the “slaves” in dehumanizing sex acts to members-only chat rooms on the encrypted messaging application Telegram, according to police.

He allegedly charged the equivalent of up to $1,200 in cryptocurrency per person to view the videos.

“ ‘The Doctor chat room’ incident is a cruel and shocking crime that dealt a shattering blow to the lives of children, teenagers and women,” said Min Gap-ryong, commissioner general of the National Police Agency. “Through stringent investigation, we will put an end to the social apathy toward online sex abuse and uproot such crime from gaining a foothold in our society.”

Police have tracked down 124 suspects and arrested 18 people since last year while investigating sex-abuse networks on Telegram and other social media platforms.

Lee Jung-ok, South Korea’s minister of gender equality, said the government has been working on strengthening the legal framework to prevent sexual abuses online since 2017.

“However, new types of digital sex crimes are emerging with advancements in information technology, triggering the need for further actions in a fast manner,” Lee said. She said the government would soon strengthen sentencing standards for online sex crimes.