Prosecutors filed a murder charge against the suspected gunman in the deadly shooting at Los Angeles International Airport, and he could face the death penalty.
Paul Ciancia, 23, remained in hospital today after being shot four times and wounded in the mouth and leg by police before his arrest.
The FBI said he was unresponsive and they had not been able to interview him.
Friday’s attack also wounded five others, including two other security officers. Security officer Gerardo Hernandez was killed. Ciancia was also charged with commission of violence at an international airport.
Ciancia said in a note that he wanted to kill at least one Transportation Security Administration (TSA) officer and did not care which one, authorities said.
US Attorney Andre Birotte Jr said Ciancia strode into Terminal 3, pulled an assault rifle out of his bag and fired repeatedly at point-blank range at a TSA officer who was checking IDs.
After shooting the officer and going up an escalator, he turned back to see the officer move and returned to fire on him again, killing him, according to surveillance video reviewed by the FBI.
Ciancia then fired on at least two other TSA employees and a civilian airline passenger, who were all wounded. Airport police eventually shot him and took him into custody.
It is not clear why Ciancia targeted the TSA, but the handwritten note found in his bag said he had “made the conscious decision to try to kill” multiple TSA employees and that he wanted to stir fear in them, said FBI Special Agent in Charge David Bowdich.
The FBI said they had not found evidence of past crimes or any confrontations with the TSA. They said Ciancia had never applied for a job with TSA.
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.
Terminal 3, the area where the shooting happened, reopened yesterday.
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.
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 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.
Mr Hernandez, 39, was the first TSA official in the agency’s 12-year history to be killed in the line of duty.
The attack at the nation’s third-busiest airport halted caused hundreds of flight delays and cancellations nationwide.
Leon Saryan had just passed through security when he gunfire. 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 toward the gate. He had his gun at the ready and, but for the grace of God, I am here to tell about it,” Mr Saryan said.
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.
“He kept to himself and ate lunch alone a lot,” a former classmate, David Hamilton, told the Los Angeles Times.
“I really don’t remember any one person who was close to him .... In four years, I never heard a word out of his mouth.”