(CNN)-- A convicted child pornographer in Pennsylvania was sentenced Tuesday to 12 years in federal prison, thanks in part to three girls featured in CNN's Freedom Project who provided information to U.S. authorities.

Jeffrey Herschell, 54, of Washington, Pennsylvania, visited an Internet site that showed live sex shows that forced young girls in the Philippines to act out customers' fantasies, U.S. investigators said.

"Whatever the American client wants us to do, we must do it," "Gen" told CNN in May 2011 for the documentary "The Fighters." "Gen" and her friends were schoolmates and just 8 years old when the abuse occurred.

An investigator from Homeland Security Investigations, part of U.S. Immigration and Customs Enforcement, told CNN the information the three girls provided him was integral to the case against Herschell.

Their information launched an investigation that uncovered a ring operating live-streaming shows of children engaging in sexually explicit conduct. Customers from around the globe, including an estimated 10 to 15 from the United States, paid to view the shows and direct them, in some cases.

When HSI agents executed a search warrant on Herschell's home in 2011, they found computers, cell phones and hard drives containing dozens of explicit videos and images of children.

The inquiry involved several U.S. agencies, the Philippines national police and the non-profit group Visayan Forum Foundation, which fights modern-day slavery.