South Korean leader of online sexual blackmail ring sentenced to 40 years

Cho Joo-bin walks out of a police station in Seoul, South Korea, on March 25.

(CNN)The South Korean leader of an online sexual blackmail ring that targeted minors and young women was sentenced to 40 years in jail on Thursday, marking the end of an explosive criminal case that sparked outrage across the country.

Cho Joo-bin, 25, hosted online rooms on encrypted messaging app Telegram, where users paid to see young girls perform sexual acts under coercion. At least 74 victims, including 16 minors, were blackmailed into uploading explicit images onto the group chats. At least 10,000 people used the chat rooms, with some paying up to $1,200 for access, officials say
After two university journalism students discovered the Telegram groups last summer, police launched their investigation, and arrested Cho in March.
    He was later indicted under 15 charges of producing and distributing illegal sexual visual material, forced sexual abuse, rape, sexual harassment, blackmailing, recording sexually abusive behaviors, coercion, violation of private information protection, and fraud.