(CNN) -- A federal judge sentenced children's author K.P. Bath to six years in prison Thursday for possessing child pornography.
Investigators found a large collection of pornographic photographs and video clips in the Portland, Oregon, home of the author of "The Secret of Castle Cant" and "Escape from Castle Cant," according to a statement federal prosecutors released Thursday.
"Many of the videos graphically depicted the sexual abuse of very young children," the statement from the U.S. Attorney's Office in Oregon said.
Bath, 51, pleaded guilty to two counts of possessing child pornography.
"It is shocking that a children's author would contribute to the trauma these kids endure -- both physical and emotional trauma from the sexual abuse itself, and psychological trauma from knowing that images of that abuse are circulating on the Internet," U.S. Attorney Dwight Holton said in a statement.
Bath's collection included images depicting sadistic conduct, rape, sodomy and bestiality, prosecutors said.
Prosecutors also allege that an investigation revealed that Bath had traded images of child pornography with at least two different collectors in Washington and Ohio.
Those collectors were prosecuted, but charges against Bath for allegedly transporting, distributing and receiving child pornography were dropped as part of a plea agreement, the U.S. Attorney's Office said.
Bath volunteered at the Beverly Cleary Children's Library in Portland and worked at The Asian Reporter newspaper, according to a 2004 University of Alabama news release describing an alumni reading series.
Bath had a master's degree from the university and had worked as a field hand, factory laborer, musician, editor and teacher, the news release said.
CNN's Catherine E. Shoichet contributed to this report.