Updated

A Republican congressman is accusing a government agency of "stonewalling" attempts to investigate allegations of animal abuse after graphic photos appeared online showing hunting dogs attacking defenseless coyotes.

The images, allegedly taken by an employee of Wyoming Wildlife Services whose job includes controlling nuisance predators, represent "flat-out animal cruelty," Rep. John Campbell of California said Monday.

Campbell told FoxNews.com that the photos are indicative of widespread problems within the little-known agency -- ranging from possible misuse of taxpayer money to alleged animal abuse of predatory and non-predatory wildlife.

The photos in question were posted by Jamie P. Olson, an employee of Wyoming Wildlife Services, a branch of the U.S. Department of Agriculture's Animal and Plant Health Inspection Service. The photo album reportedly appeared on Olson's personal Facebook account, which has since been deactivated. The photos include images of dogs snarling at and ripping into live coyotes trapped in steel foot-holes, as well as pictures of coyote carcasses.

"This is becoming a recurring theme that they are doing some cruel things -- some bad things -- and doing it all with taxpayer money," said Campbell, who, along with Rep. Peter DeFazio, D-Ore., is calling for an independent investigation into the "inhumane" practices by Wildlife Services. "They appear to be stonewalling every attempt by everybody to investigate why they’re doing it."

"We believe there's kind of a pattern here that this has become almost sport to put out these traps," Campbell continued. "We think there are a lot of non-lethal ways to protect livestock. But instead, they use these leg holes, which are extremely cruel. The animal takes a long time to die."

Campbell also said he has "increasing evidence" of taxpayer money being used for "private purposes," including protecting the livestock of four private ranchers.

"I have cattle myself," Campbell said. "I don’t think it’s the taxpayer's responsibility to protect my cattle. That’s my responsibility."

Both Campbell and DeFazio penned a letter Nov. 30 to Agriculture Secretary Thomas Vilsack calling for a thorough audit of the "culture" within Wildlife Services -- in particular its lethal predator control program -- by the USDA Office of Inspector General.

"We are gravely concerned that photographs, published on Mr. Olson's Facebook in an album labeled "work" and since removed, do not represent an isolated occurrence, but may reflect a deep-rooted problem within the Wildlife Services program that allows for, and encourages, inhumane lethal methods of predator control," the lawmakers wrote.

Wildlife Services spokeswoman Carol Bannerman confirmed Monday that the photos taken by the agency employee are still under investigation. The photos were allegedly posted in an album titled "work," but it remains unclear whether they were taken while Olson was on the job or not. The federal employee, whom Bannerman did not name, remains employed at this time. Olson could not be reached for comment.

Bannerman said if the investigation concludes that animal abuse took place, that "would not be accepted."

"We do take it very seriously," she said. "We have directives that require our staff to use the USDA standards for the removal of animals...To do it quickly with the least amount of stress."

Rep. DeFazio took issue with the USDA’s Wildlife Services lethal predator control program, which he said he had been “trying to eliminate ... for over 25 years.

"This program is ineffective, indiscriminate, inhumane, and it has cost the taxpayers hundreds of millions of dollars since it was created," he said. "It’s incredibly important that we bring the actions of this agency out of the shadows.”

The photos have sparked outrage among several environmental groups critical of the federal government's anti-predator program. The images have also led to an online petition at www.change.org that calls for Olson's termination.

"Wildlife Services is veiled in secrecy and a culture of cruelty and they hope it will all just go away if they ignore it long enough," the California-based group Project Coyote said Monday.

In a statement released to FoxNews.com, the Humane Society said it is "horrified by photos posted on Mr. Olson’s Facebook page that appear to show a coyote fighting desperately to escape from a steel leg-hold trap while Olson’s dogs ripped and pulled the defenseless animal’s body apart.

"The photos suggest Mr. Olson was acting in his capacity as a federal employee," said Stephanie Boyles Griffin, senior director of Wildlife Response, Innovations & Services for The HSUS.