The chatroom operators contacted the girls, promising modelling or escort jobs.
They were then directed to a Telegram where the operator extracted personal details which were used to blackmail them. Who were the victims?
After being promised money and a phone, she was told to send pictures of compny, followed by sexual abuse videos. The victim said there were at least 40 videos in total. His comments outside the Seoul police station will have done nothing to quell the deep wave of anger sweeping through supporters of women's rights in the country.
More than two million ed a petition to have Cho's identity made public. They got their wish.
But the fury will not stop there. Over and over again women have told me they feel chatline rooms justice system does not adequately punish sex crimes and does not act as a deterrent.
And over and over again tens of thousands of women comapny urged the current administration to act. This became apparent during South Korea's so called spy camera demonstrations.
Large-scale protests were held over several weeks at the authorities' lack of hot chat line over illicit videos - taken in places such as public toilets and changing rooms - and posted online. The Minister for Gender Equality Lee Jung-ok has vowed to revise the laws governing sex crimes including online grooming and the blackmail of children and teenagers.
But will the changes go far enough in a country where being drunk is a defence for rape? The level of outrage at this case should be a warning to the current administration that women in this country are watching closely - and will not wait forever for well overdue reforms.
Communicating to girls in a way that effectively shifts their mindset Services they need. Yet millions of girls are not using them.
Even when they are free. We create content that helps girls make choices and changes in their lives. Igniting their confidence to act differently at a time that can define ant future.
So every girl can choose to be in control of her body, her health, her learning and livelihood.