Federal prosecutors have filed multiple charges against a 23-year-old South Korean man accused of running what they call the world's "largest dark web child porn marketplace."

The now-shuttered English-language site, called "Welcome to Video," contained more than 200,000 unique videos or nearly 8 terabytes of data showing sex acts involving children, toddlers and infants, according to the 18-page criminal indictment unsealed here Wednesday, and processed 7,300 Bitcoin transactions worth more than $730,000.

According to prosecutors, the vast on-line store was run by Jong Woo Son, a South Korean citizen currently serving an 18-month prison sentence in his home country after his conviction on charges related to child pornography. The site operated from June 2015 until it was seized and shut down by U.S. authorities in March 2018.

The site allegedly rewarded its members with "points" in relation to the amount of illegal material they uploaded, authorities announced Wednesday.

One user of the site, a former federal U.S. law enforcement agent, even downloaded over 50 hours worth of videos.

Son was indicted on federal child porn charges in August 2018, which remained sealed until Wednesday.

In addition to Son, more than 100 other suspects have been arrested in South Korea, while still more suspects were identified in other countries, including the U.K. and the U.S., including a Washington, D.C. man who was caught with the equivalent of 50 years worth of video footage he had downloaded.

The website ran solely on the dark web, a section of the internet that can only be accessed via a Tor browser, which is designed to protect users' tracks online and obscure digital footprints. Users could purchase videos using cryptocurrency and an annual membership was priced at 0.03 bitcoins (at current exchange rates, around $300).

Read the full story on NBC's website.