An undercover TSA agent was able to get through security at Dallas/Fort Worth International Airport with a handgun during testing of the enhanced-imaging body scanners, according to a high-ranking, inside source at the Transportation Security Administration.

The source said the undercover agent carried a pistol in her undergarments when she put the body scanners to the test. The officer successfully made it through the airport's body scanners every time she tried, the source said.

"In this case, where they had a test, and it was just a dismal failure as I'm told," said Larry Wansley, former head of security at American Airlines. "As I've heard (it), you got a problem, especially with a fire arm."

Wansley said covert testing by the TSA is commonplace -- although failing should be rare.

The TSA insider who blew the whistle on the test also said that none of the TSA agents who failed to spot the gun on the scanned image were disciplined. The source said the agents continue to work the body scanners today.

Wansley said that is a problem.

"This was only a test, but it's critically important that you do something, because if that person failed in the real environment, then you have a problem," he said.

The TSA did not deny that the tests took place or the what the results were.

The agency would only provide the following statement:

"Our security officers are one of the most heavily tested federal workforces in the nation. We regularly test our officers in a variety of ways to ensure the effectiveness of our technology, security measures and the overall layered system. For security reasons, we do not publicize or comment on the results of covert tests, however advanced imaging technology is an effective tool to detect both metallic and nonmetallic items hidden on passengers."

TSA agents who spoke to a reporter agreed that the body-imaging scanners are effective -- but only if the officers monitoring them are paying attention.