Union and TSA officials said the officer was the first ever killed in the line of duty. The agency was founded in the aftermath of the Sept. 11, 2001 terrorist attacks.
J. David Cox Sr., national president of the AFGE, said the officer was one of the officers stationed throughout the airport looking for suspicious behavior.
Initially, Cox said at least three other TSA officers were wounded. Their conditions were not disclosed. Later in the day, the TSA said two other officers were injured.
The Los Angeles Fire Department revised its total number of victims taken to the hospital from six to five, saying one had been double counted. Those numbers included the gunman, the slain TSA officer and one person who broke their ankle.
