Christopher Blackford, 28, of North Charleston, never returned to Money Man Pawn to retrieve the laptop computer he left there in February 2011. That lapse could cost him his freedom for decades to come.

When pawnshop employees turned on his computer to get it ready for sale, they found disturbing content — photographs of children in sexually compromising positions, according to a police report. Employees at the shop called police and Blackford was arrested on April 25, 2011.

When authorities delved deeper into his secret stash, they found Blackford also went by “biggniche090” on a clandestine, international child-pornography-sharing website, according to federal court documents.

Last week, Blackford pleaded guilty in Louisiana to participating in a child exploitation enterprise that authorities describe as one of the largest child porn cases in U.S. history, involving dozens of defendants.

Blackford faces 20 years to life in prison, according to officials with the Immigration and Customs Enforcement Agency, which investigated the case.

Investigators discovered that Blackford was among those who participated in an online bulletin site called Dreamboard, which would produce and display child pornography. So far, 47 people have pleaded guilty for their participation in the website.

Dreamboard was a members-only site that was created in January 2008 to promote pedophilia and encourage the sexual abuse of young children in an environment designed to avoid detection from police, authorities said. The site was created by an unidentified suspect in the case.

Blackford is accused of being one of the site’s users. He joined on Dec. 29, 2009, according to his plea agreement.

The site had rules and regulations, which were printed in English, Russian, Japanese and Spanish, according to a federal indictment. The rules specified what kind of images were acceptable for admission to Dreamboard. One rule restricted the age of young girls that would be depicted in the pornographic photos.

“Keep the girls under 13, in fact, I really need to see 12 or younger to know your a brother,” the indictment stated. Another rule called for nudity in all photos. “And don’t avoid nudity in your previews. I will NOT accept you, if theres no nudity,” documents stated.

The site would require its users to post a certain amount of photos on a regular basis or their membership would be canceled, according to federal documents.

It also divided its users into levels of membership, with each level providing distinct access to certain sections of the board, documents stated.

Blackford started his participation with the site as a member, but he reached VIP status as a result of his postings, according to his plea agreement documents.

He contributed 84 posts to Dreamboard, according to federal authorities. It remains unclear how Blackford obtained the images he shared.

“Most of his posts were of extremely young children posing or engaging in sexual acts with adults. Because the images included prepubescent children engaging in sexual acts with adults, the material was sadistic in nature,” federal documents stated.

Blackford and another defendant, William Davis, 39, of Bristol, N.H., who pleaded guilty to conspiracy to advertise child pornography, will be sentenced on July 29 in the Western District of Louisiana, where the Dreamboard case is being prosecuted.

“The sexual abuse of innocent children is one of the most unconscionable violations of trust imaginable,” said Homeland Security Investigations New Orleans Special Agent in Charge Raymond Parmer Jr. in a statement Thursday. “Investigating and prosecuting the perpetrators of these horrendous crimes is one of our highest priorities.”

Reach Natalie Caula at 937-5594 or Twitter.com/ncaula.