Authorities have shut down a global social networking-like site where members traded child porn, talked about their fantasies and traded tips about not getting caught, according to the Department of Justice.

The investigation into the site is ongoing, the agency said, and it is working with police officials from several countries to try to find members who haven't been identified. More than 50 people have been arrested around the world and 35 convicted since the 2008 start of the investigation, dubbed Operation Nest Egg, the Department of Justice said.

The members "participated in a sophisticated, password-protected Internet bulletin board group, which existed to allow members to meet like-minded individuals with a sexualized interest in children, to discuss that interest and to trade images of child pornography," according to court documents.

At one point, the site had more than 1,000 active members.

"The individuals who participated in this Internet-based bulletin board exploited the most innocent and vulnerable in our society," Assistant Attorney General Lanny Breuer said.

The Department of Justice said the operation began by targeting 26 defendants who were charged in the Southern District of Indiana and then expanded to about 500 other individuals around the globe who were a part of the online group that was "dedicated to trading images of child pornography."

Most of the people charged are accused of conspiring to advertise and distribute child pornography, along with substantive counts of advertising and distributing child pornography.

Officials said the inquiry led them to further investigate some people for sexual abuse of children.

"Numerous members of the Internet-based bulletin board were found to have been personally sexually abusing children, sometimes producing images of the sexual abuse," the Department of Justice said in a statement.

The agency said the site's lead administrator, Delwyn Savigar of the United Kingdom, was among them.

After his arrest, Savigar's DNA led police to an unsolved sexual assault against a minor, the agency said. Savigar eventually pleaded guilty to the charge. The department said that after the one instance of assault was discovered, Savigar was linked to several other sexual assaults.

In total, Savigar pleaded guilty to abusing or attempting to abuse three minors. He was sentenced to 14 years in prison.