WASHINGTON — U.S. authorities said Wednesday they have dismantled a worldwide child pornography ring that traded illicit images over the Internet using sophisticated encryption.
Investigators said an estimated 600 people used a private, members-only Internet bulletin board called Dreamboard to access the graphic images. Federal prosecutors have filed charges against 72 people in what they described as the largest prosecution ever of an online child pornography operation.
Agents have yet to identify all those involved because of the extensive encryption used by members, NBC News reported.
A total of 62 of those charged have been arrested on five continents, including 43 in the U.S., where the ring based its Internet bulletin board, authorities said. Dreamboard has now been shut down, federal officials say.
Attorney General Eric Holder and Homeland Security Secretary Janet Napolitano announced details of the year-long investigation, dubbed Operation Delego, at a press conference Wednesday.
"The members of this criminal network shared a demented dream to create the preeminent online community for the promotion of child sexual exploitation but for the children they victimized, this was nothing short of a nightmare," said Holder.
Immigration and Customs Enforcement agents said dozens of children, in the U.S. and overseas, have been brought to safety after they were identified in the more than 27,000 images uploaded to the Internet bulletin board, NBC News reported. In addition to the U.S., arrests were made in Canada, Denmark, Ecuador, France, Germany, Hungary, Kenya, The Netherlands, the Philippines, Qatar, Serbia, Sweden and Switzerland.
While the computers hosting the site were on American soil, in Georgia, the sites top administrators were in France and Canada, federal agents said, according to NBC.
The Justice Department said in a news release that members "traded graphic images and videos of adults molesting children 12 years old and under, often violently, and collectively created a massive private library of images of child sexual abuse."
Members went by nicknames such as "Perfesser," "Beast," "Catfish" and "Bones." They accessed the board via proxy servers that routed Internet traffic through other computers so as to disguise a user's actual location, authorities said.
"Some of the children featured in these images and videos were just infants," Holder said. "And, in many cases, the children being victimized were in obvious, and intentional, pain – even 'in distress and crying,' just as the rules for one area of the bulletin board mandated."
At the press conference, Holder called the ring's actions "unconscionable." He said what made it especially dangerous was that a member's access to material on the site expanded based on the number of images each person contributed.
Lanny Breuer, in charge of the Justice Department's criminal division, said members were required to upload new material at least every 50 days to maintain their access.
"This was an extremely dangerous criminal enterprise. Dreamboard was a living horror," he said at the news conference.
"Dreamboard was extreme even among online child abuse forums. So-called 'super hardcore' images — those depicting adults having violent sexual intercourse with 'very young kids' — were highly valued."
Since the federal effort began to shut the site down, four of those charged have pleaded guilty. One of them was sentenced to 30 years in prison. Asked if such a sentence was appropriate, Holder described it as "barely adequate."
"These were some of the most disturbing images, I think, you will ever see. It's hard to imagine a penalty severe enough," he said.
The rules of Dreamboard were printed in several languages including English, Russian, Japanese and Spanish, according to the indictments. Members were classified into groups that included "VIP" and "Super VIP." The latter were producers of child porn, prosecutors said.
Several of the suspects are facing prosecution in Lafayette, La., where the investigation apparently originated, KATC reported. The U.S. attorney's office in Lafayette scheduled a separate news conference Wednesday afternoon to provide additional details.
One man linked to the ring is Joseph "Matt" Wheeler, a 31-year-old high school football coach in Buena Vista, Va., according to The Roanoke Times. Wheeler was arrested July 15 on child pornography charges and was being held in the Roanoke County Jail without bond, awaiting to transfer to Lafayette for trial, according to the newspaper.
Wheeler is a 1997 graduate of Parry McCluer High School and has served as an assistant football coach since 2002, The Roanoke Times said. At a hearing last month in U.S. District Court in Roanoke, where Wheeler was brought for a bond hearing following his July 15 arrest, a federal agent testified that Wheeler posted 78 images to the pornographic bulletin board over the past two years.
This article contains reporting from NBC News Justice Correspondent Pete Williams and msnbc.com staff.