South Korean police are tracking down members of the so-called Baksabang chat room on the Telegram messenger service that distributed photos and videos of violent sex acts involving women and minors.

According to authorities, these members paid fees to view sexual exploitation materials and may have also shared them with others.

The cyber safety division at the Seoul Metropolitan Police Agency said Thursday that officials raided three cryptocurrency exchanges -- Bithumb, Upbit and Coinone -- on March 13. 

Six days later, police conducted a search at Best Coin, a proxy firm that buys and transfers cryptocurrencies.

Cho Ju-bin, the operator of Baksabang, is accused of luring victims to obtain nude photos that show their face and using the images to threaten them to film sexually exploitative videos.

Police have confirmed 74 victims so far, 16 of whom are underage girls.