An Oregon man who federal prosecutors said had the largest collection of child pornography they have ever found in the state has been sentenced to 15 years in prison.

PORTLAND — An Oregon man who federal prosecutors said had the largest collection of child pornography they have ever found in the state has been sentenced to 15 years in prison.

Dewey Burr of Hillsboro pleaded guilty last March to distribution of child pornography.

The FBI said investigators found 1.1 million images of child pornography on his computer, including graphic images of babies and toddlers being sexually abused.

The case against Burr began in June 2009 when an undercover FBI agent in Maryland signed on to a publicly available file-sharing program as part of a continuing child pornography investigation.

In court documents, prosecutors said the agent found an individual using the screen name "Skippy20" who was logged into the same file-sharing program.

Skippy20 sent a message to the agent that said, "Feel free to browse, and take what u like. I do not judge, please do not judge me."

A sample of images taken by the agent included a naked girl, about 8 to 10 years old, kneeling on a bed with a man holding her hair and a butcher knife to her throat.

Another FBI agent in Florida working on a separate child pornography investigation also found Skippy20 logged into the same network two days later, and samples of downloaded files showed children, both boys and girls, engaged in sexual activity and bondage.

In a sentencing memo filed last week, the prosecutor in the case, Assistant U.S. Attorney Scott Kerin, noted that Burr admitted he viewed and traded child pornography on a daily basis and had been collecting images for a long time.

"The sheer volume of child pornography that the defendant possessed, over one million images, is truly staggering and well beyond what we normally see," Kerin said.

The case was filed as part of Project Safe Childhood, a national program launched in May 2006 to battle sexual exploitation of children.

According to U.S. Department of Justice figures, the number of cases filed in federal courts under the program has steadily increased, from 1,657 in 2006 to 2,315 last year.

Burr was sentenced Wednesday in U.S. District Court in Portland.