The Department of State diplomatic security officer recently snared in an undercover FBI child pornography investigation yesterday pleaded guilty to a single felony count, pursuant to a deal struck with federal prosecutors.

By copping to transporting child porn, James Cafferty, 45, now faces a mandatory minimum prison term of five years (though a judge could sentence him to up to 20 years in custody). Cafferty, who most recently was stationed at the U.S. Embassy in London, is seen in the mug shot at right.

In a plea agreement filed in U.S. District Court in Tampa, Cafferty admitted that when he returned to the U.S. from England in August, he carried three hard drives containing up to 15,000 child porn images (both photos and videos). Digital storage media found in Cafferty’s Largo, Florida home during a law enforcement search contained more than 30,000 child porn images.

During questioning by federal agents, Cafferty “admitted ‘photo-shopping’ himself into scenes constituting child pornography.”

Cafferty, who is scheduled to be sentenced on March 23, first came to the attention of federal agents in the course of an Immigration and Customs Enforcement probe that was launched in April 2006. The ICE investigation identified 5000 U.S. residents, including Cafferty, who had paid to subscribe to web sites offering child pornography. According to the plea agreement, Cafferty “was flagged” as a State Department employee who had purchased access to several of the illicit sites, including “Sick Room.”

In mid-2011, Department of Defense investigators enlisted the FBI’s help in its probe of Cafferty. Since the security officer’s subscriptions dated back several years, agents “reinitiated the investigation to determine if Cafferty was still utilizing the Internet via his Yahoo email accounts to access child pornography.”

That “reinitiation” involved an undercover FBI web site purporting to offer illicit videos for free. As detailed by TSG four months ago, that operation targeted Cafferty, who was reeled in by federal agents after he logged into the undercover site (from an IP address in London)  and sought to download a video purporting to depict “a 9-10 y.o. girl and man” engaged in a variety of sexual activity.