(CNN) — Accused LAX shooter Paul Anthony Ciancia entered a plea of not guilty Thursday to 11 federal charges, including the murder of a TSA agent.
Ciancia, 23, is accused of fatally shooting Transportation Security Administration officer Gerardo Hernandez and wounding two other officers and a passenger on November 1.
A Los Angeles police officer shot and wounded Ciancia to end the incident, according to authorities.
A grand jury on December 17 indicted Ciancia on a charge of murdering a federal officer, two counts of attempted murder of a federal officer and eight firearms-related charges.
According to the criminal complaint against Ciancia, he allegedly entered Terminal 3 at the Los Angeles airport, pulled out a .223-caliber M&P-15 semiautomatic rifle and fired several shots point-blank at Hernandez.
He began to walk up an escalator, but saw Hernandez move and returned to shoot him again, authorities allege in the complaint.
Investigators say Ciancia then fired on two other TSA officers and a passenger, all of whom were wounded, before a Los Angeles police officer chased him down and shot him, according to the complaint.
Investigators found a handwritten letter among Ciancia’s belongings at the airport addressed to TSA employees, saying the shootings were meant to “instill fear in your traitorous minds.”
The note said he had made a “conscious decision to try to kill” TSA workers, according to the complaint.
Alerted to troubling text messages sent to his family back East, Los Angeles police officers had gone to check on Ciancia the morning of the shooting but didn’t arrive in time.
They got to his apartment 52 minutes after the shooting and left without realizing his connection to the incident, according to authorities.