Federal prosecutors on Saturday filed a murder charge against the suspect in the shooting rampage at Los Angeles International Airport in which a Transportation Security Administration screener was killed.

Other charges related to firing a weapon inside an international airport were also filed against 23-year-old Paul Anthony Ciancia, who was identified by police as the man who opened fire inside Terminal 3 about 9:20 a.m. Friday. At an FBI news briefing Saturday, officials confirmed that Ciancia used an assault rifle in the attack.

If convicted, Ciancia faces life in prison without parole, or possibly the death penalty, authorities said Saturday.

At the briefing, FBI officials said Ciancia's intent was made "very, very clear" in a note in which he "indicated his anger and malice toward TSA officers."

David Bowdich, FBI special agent in charge, said that in Ciancia's  handwritten note, his goal was to "instill fear into their traitorous minds."

Ciancia remained in critical condition Saturday morning after law enforcement sources said he was shot in the leg and head by LAX police. Because of his injuries, federal authorities had not been able to interview Ciancia, Bowdich said.

Authorities on Saturday were still trying to learn a motive. But a federal law enforcement official briefed on the investigation told The Times that the note found with Ciancia contained a rant against the government and the words “kill TSA."

TSA Administrator John S. Pistole traveled to Los Angeles on Saturday to meet with the family of Gerardo I. Hernandez, 39, the screener who was shot and killed on Friday. Pistole, who was the No. 2-ranking official at the FBI from 2004 to 2010 before joining the TSA, also met the two TSA officers who are recovering from gunshot wounds, officials said.

Hernandez is the first TSA officer killed in the line of duty since the agency was created 69 days after the Sept. 11, 2001, terror attacks.

“No words can explain the horror that we experienced today when a shooter took the life of a member of our family and injured two TSA officers at Los Angeles International Airport,” Pistole said in a letter to TSA employees sent on Friday.

Authorities said that during the rampage, Ciancia approached several people cowering in the  terminal, pointed the gun at them and asked if they “were TSA.” If the answer was no, he moved on without pulling the trigger. A witness told The Times that the gunman cursed the TSA repeatedly as he moved through the terminal.

The incident was over in less than 10 minutes but caused chaos at the world's sixth-busiest airport and disrupted thousands of flights across the nation.

As gunfire rang out through the terminal, travelers and employees crawled on the floor and ducked behind planters and advertising kiosks. Passengers tripped over one another and abandoned baggage as they barreled backward through the security checkpoint.

Earlier on Saturday, Gina Marie Lindsey, executive director of Los Angeles World Airports, announced that Terminal 3 had fully reopened shortly after 1 p.m. But she warned that even as LAX was “returning to normal,” operations were “very, very busy.” 

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