Timothy DeFoggi, a former acting director of cyber security for the U.S. Department of Health and Human Services, was convicted Tuesday on federal charges of engaging in a child exploitation enterprise, conspiracy to advertise and distribute child pornography, and accessing a computer with intent to view child pornography.

A Nebraska jury handed down seven separate guilty verdicts following a four-day trial, in connection with his membership in a child pornography website operated by Aaron McGrath, 31, before his arrest, conviction and sentencing to a 20-year prison term.

MailOnline has confirmed through court records that while DeFoggi was a resident of the Washington, D.C. bedroom community of Germantown, Maryland, he used two screen aliases to communicate on the underground child-porn site: 'F***Christ' and 'PT***eater'

The name of the website was often redacted from court filings, and MailOnline has opted not to print it. But federal prosecutors mentioned DeFoggi's screen names often in court.

Sick: Timothy DeFoggi, a former acting director of cyber security for the U.S. Department of health and Human services, was convicted Tuesday on federal charges of engaging in a child exploitation enterprise, conspiracy to advertise and distribute child pornography, and accessing a computer with intent to view child pornography

This chart, from the HHS fiscal 2014 'Justification of Estimates for Appropriations Committees' related to the 'Public Health and Social Services Emergency Fund,' shows that during 2013 Timothy DeFoggi was in charge of operating-system security on all of HHS computers

Kevin Charest (top C), chief information security officer for the Department of Health and Human Services Department, was DeFoggi's boss at HHS

In one court filing, his lawyer conceded that 'In the "About Me" section of username "f***christ's" profile on "Website A," it says: "Have many perversions. Contact me for fantasy chat."

The attorney argued, unsuccessfully, that DeFoggi and his co-defendant, Zackary Austin, were engaging in harmless online fantasies.

'According to evidence presented at trial,' the U.S. Department of Justice said in a statement Tuesday, 'DeFoggi registered as a website member on March 2, 2012, and maintained his membership and activity until Dec. 8, 2012, when the website was taken down by the FBI.'

'Through the website, DeFoggi accessed child pornography, solicited child pornography from other members, and exchanged private messages with other members where he expressed an interest in the violent rape and murder of children.'

'DeFoggi even suggested meeting one member in person,' the DOJ statement added, 'to fulfill their mutual fantasies to violently rape and murder children.'

The grand jury's description of the crimes was so graphic that a judge agreed to order the redaction – the blacking out – of entire pages on the government's publicly accessible computer servers.

McGrath, a Nebraska native, ran a trio of child-porn websites through TOR, 'the onion router,' an open network within the Internet that allows users to hide from network surveillance and surf online without leaving digital footprints.

The FBI deployed a custom-made software program in a 2012 investigation it dubbed 'Operation Torpedo,' scouring every so-called '.onion' website it could find and determining which of them were related to illegal activity.

McGrath operated two of his sites on the network server 'farm' where he worked by day, and operated a third from his home computer.

Federal investigators found that he had left his administrator password blank on one of the child pornography sites. They quickly began collecting information that could identify the computers that were accessing it.

One of the sites was a child-porn Facebook knockoff frequented by DeFoggi, 56, and another two dozen defendants the government identified.

A federal grand jury indicted the former government computer security honcho on March 20, 2013. He faces sentencing in November.

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Attorney General Eric Holder helms the Justice Department, which announced DeFoggi's conviction on Tuesday in a four-day trial that involved seven criminal counts, all related to child pornography

DeFoggi's name appears on an HHS organizational chart in a planning document related to the agency's fiscal year 2014 budget request.

The document describes him as being in charge of 'OS IT Security Operations,' reporting directly to HHS Chief Information Security Officer Kevin Charest.

HHS did not immediately respond to questions about when he left his job, and whether he was on the government's payroll while his charges were pending.

Other defendants snared by Operation Torpedo are named in court documents as Kirk Cottom, Vincent Diberardino, Jason Flanary, Michael Huyck, Brandon Moore, David William Peer, Russell Glenn Pierce, Kevin Pitman, Gary Reibert, John Sebes, Thomas Spencer and Joshua Welch.

The FBI said Tuesday that DeFoggi was the sixth to be successfully prosecuted.

When he ordered DeFoggi held without bail in May 2013, U.S. Magistrate Judge Thomas D. Thalken noted that he appeared 'to have a mental condition which may affect whether the defendant will appear' if he were given bond.

It's not clear what that condition is, or whether it will have an impact on sentencing.