Paul Ciancia, 23, was charged with murder of a federal officer on Saturday. He was also charged with commission of violence at an international airport. If convicted, he could face the death penalty.
When Ciancia got a ride to LAX Friday morning, he did not have a plane ticket or plans to travel. The FBI says he was carrying a bag that contained a Smith & Wesson assault rifle and intended to kill.
According to the criminal complaint filed in federal court, Ciancia pulled the .223-caliber M&P-15 assault rifle out of his bag and fired multiple rounds at point blank range at a TSA officer in Terminal 3.
"The defendant is then alleged to have begun walking away from the wounded TSA officer, going up an escalator, and then coming back down that escalator to return and shoot the wounded officer again," U.S. Attorney Andre Birotte Jr. said.
TSA officer Gerardo Hernandez died from those gunshot wounds. The 39-year-old is the first TSA officer killed in the line of duty in the 12-year history of the agency.
Investigators say surveillance video captured the rampage. Authorities say Ciancia fired a significant number of rounds, injuring two TSA officers and a civilian before he was shot by airport police and arrested.
The FBI says Ciancia signed a handwritten note found at the scene, which stated he "made the conscious decision to try to kill" multiple TSA employees.
"He addressed them at one point in the letter and stated that he wanted to 'instill fear into their traitorous minds,'" FBI Special Agent in Charge David L. Bowdich said.
Agents have recovered five loaded magazines, unspent ammunition and bullet casings from the terminal. Authorities say the assault rifle was purchased in the L.A. area. According to the New York Times, Ciancia bought two legal guns at the Target Range in Van Nuys. No one there would comment Saturday night.
The FBI is delving into his past and present to learn what motivated his malice toward the TSA -- information they don't have directly from Ciancia. He remains hospitalized in critical condition at Ronald Reagan UCLA Medical Center.
"At this point he is unresponsive, and we are unable to interview him," Bowdich said.
People who knew Ciancia said they were shocked that he was the alleged gunman.
Terminal 3 was closed following the shooting. The terminal reopened and resumed normal operations on Saturday. The shooting disrupted hundreds of flights across the U.S. Friday, many of which were held on the ground at LAX or not allowed to take off for Los Angeles from other airports.
Throughout the day, an estimated 1,550 scheduled arriving and departing flights with around 167,000 passengers were affected, according to the airport. That included 86 arriving flights that were diverted to other airports.
Anyone with information, photos or videos of the shooting at LAX was asked to call the FBI Los Angeles tip line at (888) 226-8443 or visit laxshootingtips.fbi.gov .