US prosecutors have filed a murder charge against the suspected gunman in the deadly shooting at Los Angeles International Airport, with the 23-year-old man liable to face the death penalty.
Authorities arrested Paul Ciancia after Friday's attack, which also wounded five others, including two other federal security officers. Security officer Gerardo Hernandez was killed.
Ciancia was also charged with commission of violence at an international airport.
Ciancia appeared determined to lash out at the Transportation Security Administration, saying in a note that he wanted to kill at least one TSA officer and did not care which one, authorities said.
He "wanted to instill fear into their traitorous minds", according to the note.
He looked at me and asked, 'TSA?' I shook my head no, and he continued on down towards the gate. He had his gun at the ready and, but for the grace of God, I am here to tell about it.
It is not clear why Ciancia targeted the agency, but the note found in his bag suggested the unemployed motorcycle mechanic was willing to kill almost any airport security officer he could confront with his Smith & Wesson M&P-15 semi-automatic assault rifle.
"Black, white, yellow, brown, I don't discriminate," the note read, according to a paraphrase by a law enforcement official briefed on the investigation.
Authorities believe someone dropped Ciancia off at the airport, and agents are reviewing surveillance tapes and other evidence to piece together the sequence of events.
Terminal 3, the area where the shooting happened, reopened on Saturday. An estimated 1,550 scheduled flights with some 167,000 passengers were
impacted by the ground stop resulting from the attack on Friday, authorities said.
The TSA planned to review its security policies in the wake of the shooting. Administrator John Pistole did not say if that meant arming officers.
A few more details emerged about Ciancia, who was described as reserved and solitary.
Former classmates barely remember him, and even a recent roommate could say little about the young man who moved from New Jersey to Los Angeles less than two years ago.
Ciancia, who was shot four times by airport police, remained hospitalised on Saturday with no word on his condition. He was wounded in the mouth and the leg, authorities said.
On Friday, Ciancia's father called police in New Jersey, worried about his son after the young man sent texts to his family that suggested he might be in trouble. The call, however, came too late.
Ten minutes earlier, police said, Ciancia had walked into the airport, pulled the rifle from his bag and began firing.
When searched by police, Ciancia had five 30-round magazines, and the bag contained "hundreds of rounds in 20-round boxes", the law-enforcement official said.
Hernandez, 39, was the first TSA official in the agency's 12-year history to be killed in the line of duty.
Allen Cummings, police chief in the small town where Ciancia grew up, said the texts the suspect's family had received did not mention suicide or hurting others.
Leon Saryan, a witness of the attack, had just passed through security when the gunfire began.
He fled and as he was cowering in a corner, the shooter approached.
"He looked at me and asked, 'TSA?' I shook my head no, and he continued on down towards the gate. He had his gun at the ready and, but for the grace of God, I am here to tell about it," he said.