WASHINGTON (AP) -- Federal law enforcement officials say 72 people have been charged with participating in an online international network engaged in sexual abuse of children.
Attorney General Eric Holder and Homeland Security Secretary Janet Napolitano say a law enforcement effort called Operation Delego (del-EGG-o) investigated more than 500 people around the world since the probe was launched in December 2009.
Holder and Napolitano say those charged were involved in Dreamboard - a private, members-only, online bulletin board created to promote pedophilia.
According to documents released in the probe, members traded tens of thousands of graphic images and videos of adults molesting children 12 years old and under.
At a news conference at the Justice Department, the attorney general called the criminal activity a nightmare for the children.