Law enforcement officials on Wednesday announced the takedown of the largest child pornography site on the dark web, unsealing criminal charges against its South Korean operator and hundreds of users around the world.

The website, Welcome to Video, was described as the "largest child sexual exploitation market by volume of content," carrying more than a quarter million child pornography videos when it was taken down in March 2018.

U.S., British and South Korean officials announced the takedown at a press conference in Washington.

The bust comes amid a proliferation in child pornography, much of it traded on the dark web. According to Britain's National Crime Agency (NCA), the top 10 "most harmful" child pornography sites on the dark web have about 3 million registered user accounts.

"Children around the world are safer because of the actions taken by U.S. and foreign law enforcement to [prosecute] this case and recover funds for victims," said U.S. Attorney for the District of Columbia Jessie K. Liu.

Jong Woo Son, 23, who operated the site on the anonymous Tor network from his bedroom, was arrested last year and is now serving an 18-month prison sentence in South Korea. Son faces a nine-count federal indictment in the United States that was unsealed on Wednesday. Liu declined to comment on his possible extradition to the United States.

337 users arrested

While the site was taken down more than a year and a half ago, officials said they used leads generated by the site's server to target users over the following months.

In all, 337 users in two dozen U.S. states and 11 foreign countries have been arrested on child pornography related charges. Dozens of other suspects are under investigation.

The arrested users ranged in age from 22 to 70. Some already have pleaded guilty and been sentenced. Michael Lawson, 36, an active duty Army soldier at Fort Benning in Georgia was sentenced to 121 months in prison after pleading guilty to one count of receiving child pornography. Agents found 41 child pornography videos at his home.

"Darknet sites that profit from the sexual exploitation of children are among the most vile and reprehensible forms of criminal behavior," said Assistant Attorney General Brian A. Benczkowski.

23 minors rescued

The internationally coordinated operation resulted in the rescue of 23 minor victims in the U.S., Spain and Britain who were "being actively abused by the users of the site." U.S. officials said they're working with law enforcement partners around the world to rescue other victims.

Welcome to Video operated between 2015 and March 2018. Shunning adult porn, it allowed users to upload and download child smut. The videos traded on the site depicted pre-pubescent children, infants and toddlers engaged in sexual acts.

The site was among those to allow users to trade child pornography using cryptocurrency. Cryptocurrencies such as Bitcoin allow users to send and receive cash anonymously. During the roughly three years it was in operation, the site received cryptocurrency payments more than $370,000.

According to Son's indictment, Welcome to Video had more than 1.3 million unique Bitcoin addresses created for users, indicating the website could handle at least 1 million users.

Tracing payments

By examining Bitcoin transactions, officials were able to trace payments made to the website, identify its administrator and locate its server in Son's bedroom.

"Regardless of the illicit scheme, and whether the proceeds are virtual or tangible, we will continue to work with our federal and international partners to track down these disgusting organizations and bring them to justice," said Don Fort, the head of criminal investigation for the Internal Revenue Service.

The Welcome to Video site first came to the attention of Britain's NCA during its investigation of convicted British serial pedophile Matthew Falder, according to Paul Jenkins, a senior NCA official.

"It was following that investigation that we initiated a taskforce response into the users and enablers of the Welcome to Video site," Jenkins said.

In Britain, seven users of the site have been convicted, including one person sentenced to 22 years for "raping a five-year-old boy and appearing on Welcome To Video sexually abusing a three-year old girl," Jenkins said.

