The 17-year-old niece of a U.S. congressman was subjected to a pat-down at a U.S. airport, but what happened following the incident triggered a federal investigation.

The Transportation Security Administration is under fire for how it handled the girl and under scrutiny for how it handles passengers.

The girl's uncle said she was traveling with classmates from Southwest Christian School in Texas and was going through the Los Angeles LAX airport on a retreat to Australia.

The girl was wearing a sundress and was pulled aside for a pat-down screening.

TSA documents said that during the pat-down of her stomach area her sundress slipped, revealing her breasts in public.

Overhead surveillance video of the incident was captured. The internal TSA investigation found the incident was embarrassing and unfortunate, but also accidental.

The girl's uncle is a U.S. congressman, Rep. Ralph Hall of Texas, who said his niece was devastated.

Hall and a colleague called for a federal probe of the case.

It happened two years ago. Eyewitness News obtained the records through the freedom of information action and found U.S. air passengers had filed 17,000 complaints with TSA about enhanced pat downs since 2009.

A passenger through Carolina complained about the screening of his pregnant wife.

Through Skype, Eyewitness News found Sharon Cissna, a breast cancer survivor with a double mastectomy, who said TSA insisted on patting down her prosthetics.

"We are being touched inappropriately, yet this is the law," said Cissna.

Rich Roth is an aviation security consultant who defends TSA's decision to pull young girls aside for pat-downs, saying that terrorists will use anyone.

"They have no problem using kids. Anytime you say, 'This is going to be a group that we are not going to screen,' well that is what they look for," said Roth.

The congressman told Eyewitness News that he wanted the officer who disrobed his niece fired.

TSA said it apologized and gave the officer more training.

In a statement the TSA said, in part, that it regrets the incident that caused embarrassment to the young lady.