LOS ANGELES -- A mortally wounded U.S. airport security agent lay bleeding for minutes without help because a Los Angeles Police Department officer told responders the man was dead, a union spokesman said Friday.

The police officer was standing in front of Gerardo Hernandez, obscuring him from view as he lay bleeding, and told other responding officers that Hernandez was dead, said Marshall McClain, president of the Los Angeles Airport Peace Officers Association.

Hernandez was the first officer with the U.S. Transportation Security Administration to be killed in duty since the agency was created after the 2001 terrorist attacks.

He was shot Nov. 1 after a gunman pulled a rifle from a duffel bag in the busy Los Angeles International Airport and targeted TSA officers.

Authorities finally went to aid Hernandez after helping other wounded victims. McClain said an airport officer thought he detected a light pulse and immediately wheeled Hernandez out to paramedics -- 33 minutes after he'd been shot.

McClain said he learned about the events by speaking with airport officers who were involved.

The head of the TSA union said he was appalled at the news, calling the delay "absolutely unacceptable," according to KNBC-TV. American Federation of Government Employees president J. David Cox Sr. is calling for a "serious reexamination" of TSA security policies.

Representatives for the Los Angeles Police Department, Los Angeles Fire Department and Los Angeles Airport Police said they couldn't comment on the ongoing investigation until extensive reports are finished.

Authorities say that Paul Ciancia entered Terminal 3 with a duffel bag, pulled out an assault rifle and started shooting. They said he had a note in his bag that said he wanted to "kill TSA" and that he wanted to stir fear in them, criticizing their searches as unconstitutional.

He was shot by airport police officers four times, in the mouth and leg, before being taken into custody. He remains in fair condition at a hospital, and his doctors will determine when he's fit to appear in court.

In the chaotic moments after the gunfire began, as travellers dove to the ground or scrambled for cover in restaurants and stores, officials worried there could be bombs in the terminal and tried to determine whether the gunman had any accomplices.

Officers from multiple agencies bent down to check on Hernandez before moving on, officials said.

Police broadcast over their radios that Ciancia was in custody at 9:25 a.m., five minutes after Hernandez was shot in the chest.

Trauma surgeon David Plurad said Hernandez had no signs of life when he arrived at Harbor-UCLA Medical Center. Doctors worked for about an hour to revive him despite significant blood loss.