An Iraq War veteran who had complained that the government was forcing him to watch Islamic State videos pulled a gun from his checked bag and opened fire Friday afternoon at Fort Lauderdale’s international airport, killing five people and injuring eight, authorities said.

The bloody rampage at a quiet baggage-claim area sent people scrambling through the terminals and across the airfield at one of the country’s busiest airports, shutting down all flights for hours while paramedics and federal and local law enforcement officers flooded the scene.

The alleged gunman, identified by authorities as 26-year-old Esteban Santiago of Anchorage, was apprehended unharmed. Santiago was in federal custody Friday night following a lengthy interview by Broward County sheriff’s deputies and FBI agents. He will face federal charges, officials said.

Police did not immediately identify a motive for the attack at the Fort Lauderdale-Hollywood International Airport, which occurred just before 1 p.m. and also left dozens of people injured in the chaos that followed the shooting, but said they had not eliminated the possibility that it was terrorism.

“We are looking at all avenues,” George L. Piro, the FBI special agent in charge of the bureau’s Miami division, said at a briefing Friday night. “We have not ruled out terrorism, and we will be pursuing every angle to try to determine the motive behind this attack.”

Sen. Bill Nelson (D-Fla.) said earlier on Friday: “This could well be someone who is mentally deranged, or in fact it could be someone who had a much more sinister motive that we have to worry about every day, and that is terrorism.”

Piro described a bizarre encounter the bureau had with Santiago just months before the shooting. Santiago voluntarily walked inside an FBI office in last November, Piro said. Santiago clearly indicated at the time that he was not intent on hurting anyone, Piro said, but what another federal official called incoherent and erratic statements led agents to ask local police to take him for a mental health evaluation.

Federal law enforcement officials said that Santiago had told the FBI that the CIA was forcing him to watch Islamic State propaganda videos to control his mind. After interviewing Santiago’s relatives and conducting other reviews and checking with other agencies, the bureau closed its assessment of him. 

Late Friday night in Anchorage, law enforcement officials descended on a small house where Santiago’s name was on the mailbox, along with the names of two others. A neighbor interviewed there said that Santiago had lived there with a woman and two small children.

Santiago, a U.S. citizen with ties to New Jersey and Puerto Rico, had picked up his bag from the carousel and gone to the bathroom to load his gun before returning to the baggage-claim area and firing at people, said federal officials who spoke on the condition of anonymity to discuss the ongoing investigation.

Travelers are allowed to bring firearms with them to flights as long as the guns are unloaded, locked in a hard-sided container and in checked baggage, according to the Transportation Security Administration. Ammunition can be brought onto flights but also must be placed in checked baggage.

The firearm was the only bag that Santiago checked when he traveled alone from Anchorage, en route to Minneapolis and then Florida, said Jesse Davis, chief of police at Ted Stevens International Airport in Anchorage, where passengers routinely check their weapons. “We’re a big hunting state, so we get quite a lot of that,” said Davis.

“Everything appeared normal,” said Davis. Santiago checked in for his Delta flight more than four hours early, which was unusual, said Davis, but “didn’t call attention to himself at all.”

(Thomas Johnson,Victoria Walker/The Washington Post)

A federal law enforcement official familiar with the investigation said that the suspect did not appear to say anything during his first interactions with police that suggested a political or terrorism-related motive. According to some witness accounts, he reloaded at least once and fired on horrified passengers, then lay down on the floor in a spread-eagle position and waited for authorities to arrest him.

Officials said the suspect had acted alone. Another flurry of nervous activity erupted at the airport later Friday afternoon when there were reports of additional gunfire, but Broward County Sheriff Scott Israel said there was no evidence of a second shooting.

The shooting took place in the baggage-claim area at the airport’s Terminal 2, home to departures and arrivals for Delta and Air Canada, according to the airport. Footage from the scene inside the building captured the brutal aftermath of the shooting in the baggage area, on the airport’s lower level.

Jay Cohen was dropped off at the airport for a flight and arrived after the gunfire had stopped, finding an unusual scene at the usually bustling facility.

“The airport was like a ghost town,” Cohen, 51, a consultant, said in a telephone interview. “I didn’t see anyone around.”

It wasn’t until he walked all the way up to the Delta counter without encountering a line or a single soul that he noticed about 20 people huddled together behind a nearby concrete wall. He said he peeked over the counter and saw the Delta employees on the ground trying to cover their heads with their hands.

“Hurry up. Get behind here,” someone whispered to him, he said. “Active shooter. Active shooter.”

As he looked around the terminal he previously thought was abandoned, he now could see people hiding under benches, squished up against windows, he said. Then Cohen saw police running full speed through the terminal, some with guns drawn, others with their hands on their holsters, while police cars began screaming up to the curb.

“It went from eerie quiet from when I walked in to pure mayhem in just minutes,” he said. “It was chaos.”

Many of those at the airport expressed frustration with the lack of information Friday. Hundreds were stranded on the tarmac and not allowed off the premises for hours as authorities sought to clear the airport, looking for other danger.

Sophia Macris, 35, on her way to vacation in Florida, was on her just-arrived plane from New York when the shooting occurred.

“They held our plane on the tarmac,” she said in an interview, still standing on the tarmac outside the terminal. “First, they told us there was fire alarm in Terminal 2. Then they said emergency situation.”

After the shooting, dozens of cars pulled over onto the shoulder of nearby Interstate 595. As hundreds of people waited alongside the highway, family members and friends repeatedly tried to call loved ones who were scheduled to be on arriving flights.

Saintnatus Adition paced along the highway as police cars raced past with sirens blaring. His 71-year-old father had just landed from Haiti when the chaos began. “He called and said it got very busy all of the sudden,” Adition said. He had been frantically calling him to find out whether he was okay but had not reached him as of Friday afternoon. “Of course I am very scared,” Adition said.

Adition finally heard from his father shortly after 6 p.m.

“I was so happy,” he said. “He told me he’s okay.”

His father, along with thousands of other passengers, was still waiting in a terminal around 7:30 p.m.

As evening approached, family members and stranded airport employees lining the roads grew anxious. Police kept up a heavy presence, and an access road used mostly by airport employees was also closed and jammed with personnel - maintenance workers, taxi drivers, luggage handlers and others whose livelihoods depend on the busy airport. Most had long finished their shifts and were waiting to go home.

Lee Kospender, 53, a luggage handler, had been waiting in his truck for four hours. “We were working a flight and then saw people being evacuated. Now we’ve been out here in our cars for hours.” Pointing towards a group of officers blocking the road, he said, “I’ve talked to them five times. We can’t leave.”

All flights were suspended following the shooting, and the airport was closed, officials said. Officials at other major airports across the country, including in Los Angeles and Chicago, said they were beefing up security in response to the shooting in Florida.

President Obama was briefed on the situation and spoke by phone with Florida Gov. Rick Scott and Broward County Mayor Barbara Sharief to extend his condolences on “the tragic loss of life,” said Ned Price, spokesman for the National Security Council.

“This is a senseless act of evil,” said Florida Gov. Rick Scott (R), who traveled to the airport to make his latest public remarks in the aftermath of a shooting rampage in his state.

Julia O’Malley in Anchorage, Tal Abbady and Michael S. Rosenwald in Fort Lauderdale, and Abigail Hauslohner, Julie Tate, Jennifer Jenkins, Ashley Halsey and Dan Lamothe in Washington contributed to this report.