They used proxy servers and encryption. They used anonymous screen names like "Beast," "Bones," "Jailbird," and "Johnny_5_is_@live" to post and share their child sex abuse films. Admins carefully segregated participants according to how much they were trusted.

But none of that stopped the Department of Justice from identifying and indicting 72 people accused of celebrating the sexual abuse of children age 12 years and younger through a members-only Web forum called "Dreamboard."

"Using sophisticated methods to evade detection by law enforcement, Dreamboard members allegedly used the power and anonymity of the Internet to motivate each other to commit their horrific acts of sexual abuse of minors and trading in child pornography," announced Attorney General Eric Holder in a speech today. "No matter how savvy online predators think they are, we will find them, dismantle their networks, and bring them to justice."

Fifty-two of the 72 defendants have been arrested and charged with counts of engaging in a child exploitation enterprise, conspiracy to advertise child pornography, and conspiracy to distribute child pornography. These indictments are the fruit of Operation Delego, billed as the biggest prosecution in the US ever of "individuals who participated in an online bulletin board conceived and operated for the sole purpose of promoting child sexual abuse, disseminating child pornography and evading law enforcement."

Delego was a joint sting run by the Department of Justice and Immigration & Customs Enforcement (ICE), with the help of the European Union's Judicial Cooperation Unit. Nineteen of the Dreamboard arrests came from outside the United States.

"Dreamboard was a living horror," added Assistant Attorney General Lanny A. Breuer today. "Words cannot describe how horrific the enterprise's alleged crimes were."

How Dreamboard worked

Actually, words can describe it, and in sickening detail. The Western Louisiana grand jury indictment, unsealed today, doesn't disclose how the Feds got through Dreamboard's security wall, but it does provide an overview of how Dreamboard allegedly operated, based on instructions the government says it got from the site.

According to the indictment, Dreamboard administrators required initial applicants to post a child pornography clip in order to gain membership. Members had to post new films on a regular basis; they also had to create advertisements for their latest offerings, disclosing the Web addresses and passwords needed to access the content. Non-posters saw their accounts deleted after 50 days.

Dreamboard translated its rules into Spanish, Japanese, Russian, and English. They included the following: "Keep the girls under 13, in fact, I really need to see 12 or younger to know your [sic] a brother," and "Don't avoid nudity in previews. I will NOT accept you, if theres [sic] no nudity."

In addition, the most exclusive area of the site was reserved for members who could provide content that showed children suffering. "If the girl looks totall [sic] comfortable, she's not in distress, it does NOT belong I [sic] this section."

Members were also segregated according to the degree of original content that they provided, or the degree to which the administrators trusted them. Classifications included "Super VIP," "VIP," and "Member." According to one user's guilty plea, the "SuperVIP" level was reserved for those members actually "producing child pornography and posting homemade child pornography to the bulletin board."

What the feds found

However the DoJ got through Dreamboard's security system, its agents appear to have been able to track anonymous user names, true user identities, and the titles and file names of the movies.

Here are several indictments that illustrate what the feds were able to uncover:

69. On or about the 4th day of June, 2010, MICHAEL THOMAS BIGGS aka tommyleejones did knowingly publish on the Dreamboard Internet Bulletin Board an advertisement offering to distribute the file entitled Red07.avi, which contained child pornography. 76. On or about the 26th day of May, 2010, CHARLES CHRISTIAN a.k.a. NLN did knowingly publish on the Dreamboard Internet Bulletin Board an advertisement offering to distribute the file entitled Lolita sex party, which contained child pornography.

"Dreamboard members also encouraged the use of encryption programs on their computers, which password-protect computer files to prevent law enforcement from accessing them in the event of a court-authorized search," Holder's announcement said today.

Some of the file names mentioned in the indictment make no secret of the content, however, among them a file named "Keito_11-12_y.o._Japanese_boy_with_man."

Who were the Dreamboard users? Court documents provide some clues. Anthony Paul Sowder, for instance, is a 28-year old from Kentucky who went by the user name "ChanChadwick." Sowder admitted in a guilty plea this summer that he had joined Dreamboard on May 5, 2010 and had posted 70 items showing "minor females engaging in sexually explicit conduct," which he had recorded using his computer's webcam.

At this point, 13 of the 52 individuals arrested have pled guilty to charges and have been sentenced to prison terms of as long as 30 years. Twenty of the 72 charged have yet to be found "and are known only by their online identities."