By Steve Gorman and Dana Feldman

LOS ANGELES, Nov 4 (Reuters) - A gunman who opened fire at the Los Angeles International Airport last week, killing a federal security screener and wounding several other people, did not immediately raise suspicions when he entered the airport, police said on Monday.

The gunman entered Terminal 3 of the sprawling airport looking like any other passenger, and likely would not have been detained immediately even if an armed officer had been stationed at the front door, said Patrick Gannon, chief of the Los Angeles Airport Police.

"He came in that door as a normal traveler with a bag and he was dressed normal. He didn't raise anyone's suspicions at that point," Gannon told a news conference.

Paul Anthony Ciancia, 23, was arrested following the shooting and has been charged with murder of a federal officer and committing violence at an international airport, offenses for which he could face the death penalty if convicted.

He is accused of walking into the terminal on Friday morning and opening fire with an assault-style rifle at the entrance to a security checkpoint, killing a Transportation Security Administration officer.

Authorities said the gunman continued past metal detectors and stalked the passenger boarding area, shooting and wounding two other TSA employees and an airline passenger, before he was shot and captured. The shooting triggered pandemonium as passengers and employees ran frantically for cover.

It has also sparked debate over the safety of unarmed security screeners at U.S. airports and about the adequacy of security measures that screen passengers as they enter airport terminals but do not conduct searches on people or vehicles as they enter the airport itself.

Ciancia, who was shot by law enforcement officers before he was taken into custody, remains hospitalized in critical condition, and local media have reported that he remained unresponsive and under heavy sedation.

A law enforcement official with knowledge of the case told Reuters that as of Sunday, FBI agents had been unable to question Ciancia, who was reported to have sustained four gunshot wounds, including one to his head.

Ciancia's parents said in a statement released through an attorney that they have cooperated with investigators and expressed sympathy for relatives of the slain security agent.

'ARMED PRESENCE'?

Flight traffic throughout the airport, the world's sixth busiest, was disrupted for much of the weekend, causing a ripple effect of delays around the country. Security was stepped up at many airports and federal authorities said they were considering changes to aviation security protocols.