Seven American men have been convicted and sentenced on various charges in the case, including three who were sentenced in federal court in Indianapolis on Wednesday, the U.S. attorney's office said. Two more who pleaded guilty are awaiting sentencing.
"This operation uncovered a dangerous and depraved group of criminals who were devoted to trading sexually explicit images of children under the age of five," Assistant U.S. Attorney General Larry Breuer said in a statement.
More than 20 suspects have been captured in nine states, and authorities are investigating yet more elsewhere in the U.S., as well as Sweden, Serbia, the Netherlands and the United Kingdom.
First Assistant U.S. Attorney Josh Minkler said at an Indianapolis news conference that more than two dozen children in Indiana and elsewhere were abused in the production of the pornography.
"Children who far too often weren't old enough to comprehend the crimes committed against them," Minkler said. "Children who were raped in this state and were too young to ask for help."
Some of the suspects had legal custody of their victims, and those children have been removed, prosecutors said.
The "most prolific producer of child pornography" in the group was 26-year-old David Bostic, Assistant U.S. Attorney Brant Cook said.
Bostic persuaded parents to allow him to babysit and, thus entrusted, abused the children without their knowledge, Assistant U.S. Attorney Steve DeBrota said.
He was arrested in November 2010 after federal, state and local investigators raided his home in Bloomington, Ind., uncovering hundreds of pictures and videos on his computer of children engaged in sexual acts, including four girls aged from 2 months to 3 years and one 4-year-old boy who had been entrusted to his care.
He was convicted on 65 counts and sentenced to 315 years in prison.
Bostic's arrest heralded the launch of Operation Bulldog; further investigation of his computer led investigators to others in the group.
DeBrota said the members met though a website and traded videos and still images by email.
"When they found a like-minded individual with this particular attraction that was very powerful and helped them rationalize what they were doing — in their world — was OK," DeBrota said. "That ability to find a like-minded individual online that you couldn't find in the real world is a severe danger that comes with the Internet."
DeBrota told reporters that one suspect had an ultrasound image of an unborn baby whom the prosecutor characterized as a potential future victim. He declined to provide more details, citing the ongoing investigation.
"We have examples of offenders who were planning on having children for the purpose of having a class of victims," DeBrota said.
Shawn Kuykendall, 32, of Summerville, S.C., was sentenced Wednesday to 25 years, while 23-year-old Javahn Algere, of New Orleans, got 12 years and 21-year-old Richard Szulborski, of East Texas, Pa., was sentenced to a 15-year term.
Sentenced earlier were Bostic; Danny L. Druck, 58, of Louisville, Ky., eight years; Chris Reid, 37, of Saginaw, Mich., 35 years; Todd King, 41, of Crestline, Calif., eight years.
Nicholas King, 28, of Bellingham, Wash., and 22-year-old Jeremy Labrec, of Lubbock, Texas, have pleaded guilty and await sentencing, prosecutors said.
"Child pornography rings pose a threat to children around the world and we will continue to aggressively investigate and prosecute those who participate in such groups," Breuer said.
Operation Bulldog was a result of Project Safe Childhood, a nationwide Department of Justice initiative to combat online child sexual exploitation and abuse.