From Peter Hecht:

In a major operation targeting child pornography, officers for a Sacramento Valley Internet crimes task force Tuesday arrested 15 men on charges of producing, downloading or distributing sexual images of children.

Meanwhile, a Citrus Heights man was sentenced in federal court in an unrelated case for possessing more than 50,000 pornographic images of minors.

Those arrested in Tuesday's sweep of five Valley communities included a 38-year-old Elk Grove man accused of being directly involved in the production of child pornography.

Sacramento Sheriff's Department spokesman Sgt. Tim Curran said Bradley Dayley of Elk Grove was booked at Sacramento county jail on suspicion of possessing and distributing child pornography.

He said Dayley is also facing federal pornography indictments and is under investigation for alleged child abuse of two victims younger than 14.

"He was was exploiting children by photographing and filming them in his home," Curran said.

Authorities said suspects were arrested on suspicion of downloading or distributing child porn through the Internet. They were tracked after authorities served 20 search warrants, examined computer equipment and discovered some 50,000 pornographic photos or videos of children.

Two Roseville brothers who were taken into custody had a sizable collection, Curran said.

"They had over 35,000 computer files that they shared between the the two of them," Curran said. And each of those files contains many, many images," Curran said.

Samuel Coburn, 31, and Matthew Coburn, 24, face charges of possessing and receiving pornographic images of children.

Authorities seeking a total of 18 suspects served search warrants in Sacramento, Roseville, Citrus Heights, Elk Grove and Stockton. Three suspects are still at large.

The Sacramento Valley Internet Crimes Against Children Task Force undertook the investigation. The unit is composed of officers from the Sacramento County Sheriff's Department and 47 other local, state and federal agencies.

Also Tuesday, a 27-year-old Citrus Heights man was sentenced to 13 years, four months in federal prison for possessing and transporting depictions of minors engaged in sexually explicit conduct.

Authorities say Nathan Allen, who pleaded guilty in September to child pornography charges, maintained a collection of more than 54,000 sexually explicit images or videos of minors.

Under the sentence handed down by Senior U.S. District Court Judge Lawrence K. Karlton in Sacramento, Allen was ordered to serve a 10-year term of supervised release after his release from prison.

He was also ordered to pay $7,500 in restitution to one of the victims depicted in videos he distributed.