A former comic book store employee pleaded guilty Monday in federal court to receipt and possession of child pornography as part of a plea deal with prosecutors that helped him avoid facing additional charges.

In addition, the government agreed to drop a third charge against Jacob Riley Garner, 22, who had worked as assistant manager at a comics and gaming store in The Woodlands.

The case was brought as a result of Operation Pacifier, an FBI sting unprecedented in scope in which agents took over the server of a dark website that peddled sexually explicit images and videos of children.

The FBI seized the server for the illegal website, Playpen, and kept it running for weeks in early 2015, while agents hacked into the system and identified thousands of distinct visitors. They ultimately filed charges against more than 135 users trying to access the site from within the United States.

Some defendants have opted to challenge the FBI takeover as a violation of the 4th Amendment, alleging the search warrant - pursuing anyone and anything they found on the server - was too broad.

Defense attorneys in district courts around the country have been sharing legal briefs and submitting one another's arguments in Operation Pacifier cases in their local jurisdictions.

Locally, a former MD Anderson pediatrician tried to walk back a guilty plea to three child pornography charges stemming from the Operation Pacifier sting, alleging the FBI agents had overreached. On Aug. 30, a federal judge in Galveston rejected that request and Dennis P.M. Hughes' sentencing is now pending.

Garner was arrested several months after Hughes' high-profile arrest and indicted in March on charges of receiving, accessing and possessing child pornography on Playpen on Feb. 22, 2015. An agent said in a sworn statement the investigation had uncovered 2,500 images and videos of children under the age of 12 being subjected to violence and bondage, including some children known to the National Center for Missing and Exploited Children.

Garner's attorney, Joshua Lake, said his client is aware of the legal challenges to the FBI sting but said Garner opted to plead guilty nonetheless.

He remains in federal custody pending sentencing Dec. 5. He has no prior felony convictions.

U.S. District Judge Kenneth M. Hoyt explained that as part of Garner's plea deal, the assistant U.S. Attorney on the case agreed not to pursue charges against Garner on allegations he produced child pornography featuring digital content of a minor.