TIME reports on the global cyber scam operation known as “pig butchering” that originated in China six years ago. The scam involves creating fake profiles on social media and dating sites to build online relationships with unsuspecting victims, often from the U.S., Europe, and other Western countries.

The scam has become a growing international issue, with an estimated hundreds of thousands of people, mainly in Southeast Asia, involved. Scammers like Mark Santos*, a 26-year-old Filipino, are victims themselves, lured through fake job ads or lucrative offers and then trafficked and held captive by organizations running the scam centers.