A California man was sentenced to 15 years of imprisonment for digitally blackmailing two 14-year-old Wyoming girls to make child pornography, a federal judge ruled today.

Chase McKay Stagner also will be on supervised release for another 15 years after his release from custody, and he must pay $5,000 to the Justice for Victims of Trafficking Act, according to the sentence handed down by U.S. District Court Judge Scott Skavdahl in Casper.

In May, Stagner was indicted and arrested in Chico, Calif., and extradited to Wyoming.

Later that month, pleaded guilty to two counts -- one for each girl -- that he "knowingly employed, used, persuaded, induced, enticed, or coerced a minor" to produce child pornography that he would transmit by computer or other means.

Two other counts of transporting child pornography were dismissed as part of a plea agreement that included two concurrent 15-year prison terms. However, Skavdahl added five years to the plea agreement recommendation of 10 years.

The complicated case involved Facebook and Snapchat, various pseudonyms, and a lot of fear.

On Nov. 28, the Sheridan County Sheriff's Office contacted agents with the U.S. Immigration and Customs Enforcement, Homeland Security Investigations, according to the affidavit written by one of the agents.

The girls had told the Sheriff's office they were coerced into making sexually explicit images of themselves on Snapchat on their cell phones from August through October.

The girls said they were contacted by someone, "Crystal," claiming to be a former friend who said she had nude photos of them and would leak the photos to family and friends if they didn't respond to her requests.

One girl said she had never made nude photos, but was scared, made some images and sent them to "Crystal," who demanded more explicit images and videos.

Meanwhile, the girls were friended through Facebook Messenger by someone, "Nicole Rusch," who knew someone who was extorted by "Crystal."

But one of the supposedly helpful new friends also demanded nude images.

Agents determined all the pseudonyms belonged to Stagner.