The police eventually located Mr. Cho, and when he was arrested in March, they withheld his identity from the public in their usual policy of protecting the identities of suspects in order to respect their rights and those of their relatives. But millions of South Koreans have joined an online petition asking the government to reveal his name and image, and identify all customers of online chat rooms run by Mr. Cho and others like him.
Eventually the police released his name and allowed news outlets to take pictures of him. They said they made an exception because he was charged with particularly heinous crimes.
After his arrest, Mr. Cho told reporters, "Thank you for stopping my life as a devil that I couldn't stop." During his trial, he admitted most of the charges, but denied blackmailing women. He has a week to appeal Thursday's verdict.
Several customers have reported to the police and one killed himself, according to local news reports. In August, a 26-year-old man was sentenced to two years in prison for accessing personal information about women in a database at a government office that he then sold to Mr. Cho. On Thursday, Mr. Cho's three accomplices were sentenced to terms of between five and 15 years in prison. Two clients who paid to view the explicit footage were sentenced to eight and seven years in prison.
In recent years, South Korean police have taken action against sexually explicit file-sharing websites as part of an international effort to combat child pornography. They said they soon realized that much of the illicit pornography trade had migrated to online chat rooms through messaging services such as Telegram. Since then, they have arrested dozens of people who were involved in the operations. That month, a 38-year-old former clerk was sentenced to seven years in prison for running similar chat rooms under the pseudonym "The Watchman".
Amid talks surrounding the #MeToo movement, widespread Seoul Mayor Park Won-soon killed himself in July after one of his secretaries went to the police station and charged him with sexual harassment.
In 2017, South Korea revised laws to tighten the punishment for spycam pornography – the use of tiny, hidden cameras to film female victims, often in public bathrooms. After Mr. Cho's case hit the headlines, President Moon Jae-in promised a full investigation and severe punishment of the online chat room operators and customers.