David Steiger walked off his Philadelphia-to-Fort Lauderdale flight Friday afternoon and straight into pandemonium.

The 40-year-old restaurateur had left the baggage claim just before 1 p.m. when a panicked crowd rushed toward him as they ran into Terminal 3 of Fort Lauderdale-Hollywood International Airport.

Some were crying. Others, he said in an interview Saturday, screamed: "There's a shooter!"

"I didn't know if it was real," said Steiger, of Garnet Valley. "I didn't know if it was a false alarm or if people were playing a joke. I looked around at security and they didn't seem to be aware that anything was happening just yet."

One terminal over, chaos was unfolding.

Esteban Santiago, a 26-year-old former National Guardsman from Anchorage who had served time in Iraq, opened fire in Terminal 2 about the same time Steiger was making his way out through the building next door.

Using a 9mm semiautomatic handgun believed to have been legally checked on his flight from Alaska, Santiago fired shot after shot, killing five people and wounding six others, authorities said.

Panicked witnesses fled the terminal and spilled onto the tarmac. Others hid in bathroom stalls or crouched behind cars or anything else they could find as police and paramedics rushed in. When he ran out of ammunition, witnesses said, Santiago surrendered.

Family members have identified three of the victims who died in the attack: Olga Woltering, an 84-year-old grandmother traveling with her husband from Atlanta; Michael Oehme, 57, of Council Bluffs, Iowa, who was due to embark on a Caribbean cruise with his wife, who was also shot but is expected to recover; and Terry Andres, 62, of Virginia Beach, who grew up and attended high school in Millville, N.J.

But Steiger - the director of operations at Harvest Seasonal Grill and Wine Bar in University City - described a surreal scene in the early moments of the attack.

"Half the airport didn't seem to know what was going on," he said. "There were some people running into Terminal 3 panicking and crying, and then there were people - including the security guards there - that didn't seem to realize anything had happened."

Steiger left Terminal 3 to wait for his ride just as police cars began to arrive at the scene. A panicked woman ran up and asked to hide behind him, he said.

They both looked toward the flashing lights and saw a growing crowd of worried travelers gathering at the building across the street.

"We weren't really sure what was going on," he said. "There were no announcements over the loudspeakers or anything."

Steiger said he didn't see the shooter and isn't sure if he heard any of the shots.

In fact, it wasn't until his ride picked him up and they were outside the airport grounds that he learned - via a concerned text from his wife back in Garnet Valley - what exactly had happened. Authorities would lock down all terminals moments later.

"I still can't believe I was right next to it," Steiger said. "I wasn't in danger like some people, but it was shocking. I spent the rest of the day in reflection."

Flights resumed at the airport early Saturday, said airport CEO Mark Gale, who, until taking the job in Florida last year, had led operations at Philadelphia International Airport.

Santiago was charged Saturday. His aunt, Maria Ruiz Rivera, told NJ Advance Media on Friday that her nephew recently became a father and had been hospitalized for mental-health issues after returning from a one-year deployment to Iraq in 2011.

"He lost his mind," Ruiz Rivera said in Spanish at her home in Union City, N.J.

Santiago was discharged in August for unsatisfactory performance, according to the Alaska Army National Guard.

At a news conference Saturday, FBI agents said the bureau has interviewed 175 people across the country and continues to comb through Santiago's social media profiles for signs of a possible motive. Santiago, himself, has been cooperating with agents and spent several hours talking to investigators, FBI agent George Piro said.

"Indications are that he came here to carry out this horrific attack," said Piro. "We have not identified any triggers that would have caused this attack. We're pursuing all angles on what prompted him to carry out this horrific attack."

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The Associated Press contributed to this article.