Feds Arrest 50 in Bust of Child Porn Ring

Updated at 7:11 p.m. ET

Federal prosecutors announced Wednesday that they had broken up a major online international child pornography ring that operated as a hierarchy and at its peak had more than 1,000 members trading millions of sexually explicit images.

More than 50 people have been arrested in several states since the 2008 start of the investigation, and authorities are seeking the extradition of several suspects from overseas, U.S. Attorney Tim Morrison said at a news conference. He was joined by immigration and postal officials, whose agencies took part in the investigation.

"This is the largest crimes against children case brought anywhere by anyone," Assistant U.S. Attorney Steven D. DeBrota said.

CBS News Affiliate WISH-TV in Indianapolis reports that one suspect, Edward Oedewaldt, 47, was expected to appear in Indianapolis federal court Wednesday. He was arrested in April for charges of conspiracy to advertise child pornography, conspiracy to distribute child pornography, distributing child pornography and advertising child pornography.

Oedewaldt's attorney, Howard Bergstein, declined to comment Wednesday.

DeBrota said the government is seeking the extradition of several suspects from abroad, although he didn't specify from which countries. Among them is the group's alleged ringleader, Delwin Savigar, who is serving a 14-year prison term in England for sexually assaulting three underage girls, he said.

DeBrota said Savigar administered a password-protected website where members could access collections of sexual images — some including as many as a million files — share their fantasies about having sex with children and give advise each other about how to build their collections and avoid getting caught.

The group had about 1,000 members at its peak, and about 500 when U.S. officials took down the website in 2008, DeBrota said. It was hierarchical, and higher-ranking members had more advanced privileges.

Group members generally knew each other only by their screen names, Morrison said.

The investigation was kept sealed for so long to avoid tipping off suspects. A rapid-response computer forensics team led by the Indiana State Police traced the groups' high-ranking members from one computer to the next, DeBrota said.