Distributing child pornography to an undercover agent in an Internet chat room sent a Billings man to federal prison for nine years.

Senior U.S. District Judge Jack Shanstrom on Wednesday sentenced Charles Lawson Tucker, 48, to the low end of a guideline range that went up to about 11 years.

Tucker pleaded guilty in March to distributing and receiving child porn. The judge earlier dismissed a possession count.

Tucker apologized for what he called his “despicable actions.”

An investigation found that Tucker was distributing child porn to an undercover agent in Missouri while chatting online. A search warrant served on Tucker’s home in January 2010 found 597 images and movies on Tucker’s computer, including prepubescent children engaged in sadistic or masochistic abuse.

Tucker’s attorney, Vern Woodward, argued for a five-year sentence, which was the minimum mandatory by law, saying the sentencing guidelines were unfair.

Woodward called Tucker a decent human being who also was a drunk and who got into child porn because he was depressed and lonely.

Woodward challenged the guidelines, which make receipt and distribution of child porn more serious crimes than possession. Why receiving child porn is more heinous than keeping it “is beyond me,” he said. “I don’t get the distinction between possession and receipt,” he added.

Referring to another Billings child porn case in which James H. Peak, a former Billings Clinic child psychiatrist, pleaded guilty on Wednesday to a possession charge, Woodward said in court records that the doctor was charged with simply possessing the material, although he admitted buying and receiving child porn through the mail for years.

“There’s no logic here. There’s simply politics,” Woodward said.

“Where to start, your honor?” replied Assistant U.S. Attorney Marcia Hurd.

Hurd said the U.S. Attorney’s Office charges the most serious offenses it can prove.

For receipt and distribution charges, the government has to prove someone knowingly received and distributed child porn, she said. It is more difficult to know if something received, like getting a computer file, is child porn, she said. Deciding to keep child porn becomes possession, she said.

Tucker, Hurd said, got caught because he distributed child porn to an undercover agent.

“The alcohol he used did not cause him to be a child pornographer. He did it at work. Decent human beings do not distribute,” she said.

Contact Clair Johnson at cjohnson@billingsgazette.com or 657-1282.