When FBI agent Ken Hillman was assigned to Northwest Georgia, his aim was clear: catch sex predators who target children online.

But on Friday, Hillman stood in front of a federal judge and pleaded guilty to a crime of his own; disclosing sensitive law enforcement material to his married mistress.

Senior U.S. District Court Judge Harold Murphy fined the veteran agent $1,000 and sentenced him to six months probation despite the prosecutor’s request for a $3,000 fine and four months probation.

RELATED: Former FBI agent’s actions may jeopardize child sex prosecutions

MORE: Ex-FBI agent pleads guilty 

“It’s an embarrassment to the Federal Bureau of Investigation and law enforcement in the area Mr. Hillman had worked in for years.,” Murphy said. “Here we have a man who made a bad mistake, an inexcusable mistake … and he has to be punished.”

Speaking to the judge, Hillman said he allowed Angela Russell, along with her husband Emerson, to participate on a law enforcement task force he ran because he was trying to expand the team monitoring internet chats and emails from would-be “travelers” — men and women who would come to northwest Georgia to meet children willing to have sexual relations with adults.

Attorney Steve Sadow, right, stands alongside witness Angela Russell at the Catoosa County Courthouse on Friday, May 8, 2015. Photo: Courtesy Chattanooga Times Free Press

Credit: Doug Strickland /Times Free Press

icon to expand image

Credit: Doug Strickland /Times Free Press

Hillman said his judgment was flawed because he suffered post traumatic stress disorder from the hours and hours he spent chatting with pedophiles and watching videos of adults “raping children.” He blamed the FBI for ignoring his requests to be pulled off the assignment.

“I tried to get out of it. It was horrible work. They knew it,” said Hillman, who is retired for medical reasons.

But Assistant U.S. Attorney William Witherspoon said Hillman “chose not to use” any of the protections the FBI offered and he questioned why if the work was so terrible why would he put Angela and Emerson Russell in positions to witness it.

“He didn’t just violate DOJ (Department of Justice) policy. He violated federal law,” Witherspoon said. “This wasn’t a failure of the FBI. It was a failure of Mr. Hillman.”

Hillman, who was with the FBI 17 years, established the joint local-federal Internet Crimes Against Children Task Force in Northwest Georgia in 2007. His lawyer said the task force was responsible for more than 100 arrests and “rescued” at least 15 children.

“Ken was enmeshed in the world of filth and inhumanity,” said his lawyer, Todd Alley.

Hillman’s escapades came to light after a Ringgold lawyer, investigating a case the agent’s task force had brought against his client, learned that Angela Russell had accompanied Hillman to his interrogation. The attorney, McCracken Poston, eventually learned that Hillman was involved in a sexual relationship with Russell and was allowing her and her now-former husband to do work with task force cases.

Attorney McCracken Poston pictured in 2002 entering the Walker County Sheriff’s Office. (T. LEVETTE BAGWELL/STAFF)
icon to expand image

Poston reported his findings to the FBI in 2013. The task force would eventually be disbanded.

Court records show Hillman allowed the Russells to participate in sting operations. At one point, Hillman allowed Angela Russell to help him lure sex predators through online chats where she posed as an underage girl.

While operating out of an apartment that Emerson Russell rented to the task force, Hillman let the Russells watch internet chats during which agents, pretending to be underage girls, negotiated sexual encounters with suspects, court records show.

Prosecutors also said the married FBI agent let Angela Russell review the “specialized internet chat language” and conduct several chats on behalf of the task force.

Hillman also allegedly let Angela and Emerson Russell go with him to make arrests and to put handcuffs on suspects.

“Ken made a bad decision because he had been driven to that point by his own dedication (to the task force),” Alley told the judge.

Poston argued that Hillman — whose sentence will not require prison time — received a “sweet deal” because he was a federal agent.

Murphy said while Hillman had broken the law, “the people that he and his associates were attempting to deal with on the telephone and on the internet were the real villains.”

“On occasion, I have wondered how he was able to deal with the trash,” the judge said.

Hillman on Friday described a job that involved going into online sites that became worse and worse.

“I can’t tell you how many times I saw these prepubescent children raped by these monsters. My job was to find these monsters and put them in a cage,” he said.