A Casper man who pleaded guilty to transporting child pornography will spend 14 years behind bars, federal judge ruled Thursday.

U.S. District Court Judge Alan Johnson also ordered William David Larson to be on probation for 10 years, register as a sex offender, and pay $3,000 in restitution, according to minutes of the sentencing.

A second count of possessing child pornography was dismissed at the sentencing as part of the plea agreement when Larson pleaded guilty March 23.

He was 19 at the time of his arraignment in January.

The government regards child pornography as a crime of violence because it involves sometimes brutal assaults on children who cannot give consent to sexual activity.

The case started in December when a Wyoming Division of Criminal Investigation agent who works on the Internet Crimes Against Children Task Force received information about Larson and his possible involvement with child pornography, according to an affidavit.

The agent obtained a search warrant for his residence on Cottontail Lane in west Casper, and he and other law enforcement officials executed the warrant on Dec. 22.

They seized three cell phones, a laptop computer, and two USB drives. An analysis of one cell phone revealed a 61-second video of the molestation of a girl between three to five years old.

During an interview, Larson told the agent he used his cell phone -- often with Kik Messenger software program -- to receive, possess, view and distribute images of child pornography. The Kik program preserves users' anonymity and prevents users from being located on the service through any information other than their chosen username.

Larson told the agent his username on Kik was "Sinfulflame" and that he received images from and had conversations with a Kik user who used an identifier "Amy K" and had the username "gamerchick." Larson then forwarded those images to another Kik user named "Maria," according to the affidavit.