 -- A former top federal official was sentenced to 25 years in prison today after being convicted of participating in a child pornography ring that sources say was so depraved, it even shocked veteran investigators.

Timothy DeFoggi, the former acting director of cyber security at the U.S. Department of Health and Human Services, was convicted of using an anonymous computer network to access child pornography, solicit child pornography, and exchange private messages with other network members across the county. But most shocking to investigators, sources tell ABC News, is what DeFoggi said in some of those private messages. According to evidence presented at trial, DeFoggi expressed an interest in the violent rape and murder of children. DeFoggi even suggested meeting one member of this child porn network in person to fulfill their mutual fantasies to violently rape and murder children, according to the Justice Department.

DeFoggi, 56, formerly of Germantown, Maryland, was convicted on Aug. 26, 2014, following a four-day jury trial before Chief U.S. District Judge Laurie Smith Camp in the District of Nebraska of engaging in a child exploitation enterprise, conspiracy to advertise and distribute child pornography and accessing a computer with intent to view child pornography.

In a statement issued after DeFoggi’s sentencing, Assistant Attorney General Leslie R. Caldwell said, “Using the same technological expertise he employed as Acting Director of Cyber Security at HHS, DeFoggi attempted to sexually exploit children and traffic in child pornography through an anonymous computer network of child predators."

According to Caldwell, DeFoggi was a registered member of a child pornography website that used advanced technology and the Tor-network to hide from detection. Sometimes called the “Dark Net,” the Tor-network facilitates anonymous communication, and is often used by people who want to keep their web activities private, and hidden from officials or investigators. Nonetheless, the FBI discovered this Tor-based porn site, and took it down in December of 2012.

Caldwell said, “Dangerous criminals cannot be allowed to operate on-line with impunity. Today’s sentence shows that the Department of Justice will bring criminals and child predators to justice, even when they employ anonymous networks like Tor.”

DeFoggi is the sixth person to be convicted as part of an ongoing, federal investigation targeting three Tor-network-based child pornography websites. The Justice Department said the websites were run by a single administrator, Aaron McGrath, who was previously convicted in the District of Nebraska of engaging in a child exploitation enterprise in connection with his administration of the websites. On Jan. 31, 2014, McGrath was sentenced to 20 years in prison.

These cases were brought as part of Project Safe Childhood, a nationwide initiative to combat the growing epidemic of child sexual exploitation and abuse launched in May 2006 by the Department of Justice.