>>> good evening. they are the men and women in blue. it is an unmistakable bright blue , and frequent fliers know them instantly as the people standing between us passengers and actually boarding an airplane. there was no tsa before 9/11 and they have grown big and powerful in just the years since. most of the time they do their work without incident, but tonight there is new trouble. it is a government report out about wrongdoing in the tsa for failing to discipline airport screeners who break the rules, and that ranges from sleeping on the job to letting friends and baggage through, to stealing from passengers. it is where we begin tonight with our justice correspondent pete williams . he's at washington national . pete, good evening.

>> reporter: brian, good evening. the number two official of the tsa acknowledged today that it has its share of what he calls knuckle heads. the issues, are they disciplined consistently and do the worst offenders get the harshest punishment? example, says the government accountability office , an airport screener caught on surveillance video, running carry ones through a metal detector without stopping to review each image. suspended 30 days . at another airport, a screener walks away to help a family member at the ticket counter, then takes the family carry-on and bypasses screening, suspended 7 days . and the gao told congress today that half the screeners who fall asleep on the job receive less than even a minimum level of discipline called for by tsa's own policies.

>> rather than punishing the employees using standard penalties, tsa chose to go easy on those who find it hard to stay awake while protecting the american people .

>> reporter: the report says misconduct cases at tsa went up 27% over the past three years, about 9600 in all, most for failing to show up as scheduled, violating security rules, or sleeping on duty.

>> of the 9600 cases, about half resulted in letters of reprimand, 31% resulted in suspensions, and 17% resulted in the employee's removal from tsa.

>> reporter: tsa insists it is tough on the worst offenders, firing 380 employees over the past decade for theft, for example. including a screener at the orlando airport, who admitted stealing four laptop computers from passenger baggage.

>> if we can prove an individual is stealing, if we can prove that an individual is taking drugs, if we can prove that an individual is intentionally subjugating the security system and we can prove it immediately they're out the door.

>> reporter: but says the tsa, without definitive proof, employees get letters of reprimand while complaints are investigated. still, the agency says in a workforce of more than 56,000, most of them professional, bad things are bound to happen.

>> we're going to have people that sometimes do stupid things.

>> reporter: still, the report says tsa could keep better tabz on employee discipline to make sure the punishment fits the offense, and to make sure its uniformed throughout the 450 airports where tsa screeners work. brian?

>> pete williams surrounded by happy passengers in washington, d.c. tonight.