(CNN)Esteban Santiago went to baggage claim and picked up his one piece of checked luggage.
There were no other bags, just a case with a handgun inside.
Santiago allegedly took the 9 mm handgun out of its case and fired at other travelers Friday afternoon, killing five people at the Fort Lauderdale airport. On Saturday, authorities revised the number of wounded to six after earlier saying eight.
A few months earlier he reportedly had a mental evaluation after a bizarre visit to an FBI office in Alaska.
Friday's shooting sent the airport terminal into chaos, with people running for cover. They started running again when rumors of more gunshots and a possible second shooter spread through the busy airport. Almost 40 others would get hurt in the rushed evacuation after the attack. Some suffered sprains and bruises; others had broken bones.
Here's what we know about the deadly shooting and what officials have said about the suspect:
Who is Esteban Santiago?
Law enforcement officials identified Esteban Santiago, 26, as the suspect in the five deaths at Fort Lauderdale-Hollywood International Airport.
Santiago didn't resist when he was taken into custody, Broward County Sheriff Scott Israel said. According to his booking information, Santiago is being held without bond on a murder charge.
He lives in Alaska, where he was a security guard.
Suspect Esteban Santiago is being held in federal custody in Florida.
Alaska was also the site of his last military assignment. He was a member of the Alaska Army National Guard from November 2014 until August when he was discharged for unsatisfactory performance, a spokeswoman for the guard said.
In November, Santiago paid a visit to the FBI office in Anchorage, telling agents he was hearing voices and being directed by a US intelligence agency to watch ISIS videos, law enforcement sources told CNN.
George Piro, the FBI's special agent in charge in Miami, told reporters that Santiago was turned over to local authorities and he voluntarily submitted to a mental health evaluation.
"His erratic behavior concerned FBI agents," Piro said Saturday.
The military said Santiago's nine years of service in the National Guard included one 10-month tour of Iraq, where he was awarded a combat action badge.
Santiago returned from Iraq a changed man, his aunt told CNN on Saturday.
"His mind was not right," the aunt, Maria Ruiz Rivera, said in a phone interview in Spanish from her home in New Jersey. "He seemed normal at times, but other times he seemed lost. He changed."
She added, "He talked about all the destruction and the killing of children. He had visions all the time."
Ruiz said she lost contact with Santiago several months ago.
"He stopped calling," she said. "He wouldn't respond to my messages. I would call and text. He seemed distant."
Her family is still in shock.
"Who would have imagined that he could do something like this?" she said. "I don't say that because we're family. I say it because he wasn't like that."
How did he get to Fort Lauderdale?
Piro said Santiago flew from Anchorage to Minneapolis to Fort Lauderdale on a Delta Air Lines flight.
More on the shooting
Story: 5 dead; suspect had gun in bag
Photos: Scene at the airport
Story: What's known about the suspect
Story: Witnesses describe 'war zone'
Video: Inside the airport
Video: 'I just ran'
Story: Flying with firearms
A lieutenant with the Anchorage airport police said Santiago had one bag -- a handgun case with a pistol inside that he checked.
Authorities do not know why Santiago was in Fort Lauderdale.
But Piro said Saturday that Santiago "came here specifically to carry out this horrific attack."
"We have not identified any triggers that would have caused this attack," he said.
Piro said investigators were looking at airport video to see how the rampage unfolded. Authorities have conducted more than 100 interviews as part of their investigation.
What was the motive?
The FBI has not ruled out terrorism, Piro said, but Israel cautioned it was early in the investigation and authorities did not know Santiago's motive.
Photos: Fort Lauderdale airport shooting
Photos: Fort Lauderdale airport shooting
People run out on the tarmac in the aftermath of the shooting Friday, January 6, at the airport in Fort Lauderdale, Florida. Five people were killed and eight others were wounded, officials said.
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Photos: Fort Lauderdale airport shooting
People stand on the tarmac at Fort Lauderdale-Hollywood International Airport after a gunman opened fire inside Terminal 2 on Friday, January 6.
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People take cover outside the airport in the chaos following the shooting.
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Photos: Fort Lauderdale airport shooting
Law enforcement personnel arrive in an armored car outside the airport.
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Photos: Fort Lauderdale airport shooting
Law enforcement personnel stand outside a garage area at the Fort Lauderdale-Hollywood International Airport.
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Photos: Fort Lauderdale airport shooting
Police assist people seeking cover outside Terminal 2 at the Fort Lauderdale airport.
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People react after the shooting at the Fort Lauderdale airport. The first call about the incident came in at 12:55 p.m. ET, authorities said.
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Officials said it's too early in the investigation to know for certain what prompted a man to open fire on people at the baggage claim area in Terminal 2.
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Law enforcement officers arrive at the Fort Lauderdale-Hollywood International Airport.
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A shooting victim is taken into Broward Health trauma center in Fort Lauderdale. Eight people were being treated there after they were injured at the airport, officials said.
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Police officers stand on the perimeter road at the Fort Lauderdale-Hollywood International Airport.
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A ground stop was issued for the Fort Lauderdale airport after the shooting. Most flights scheduled to land will be delayed or diverted, and no flights will depart for the time being, the FAA said.
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On Saturday, Piro said investigators "continue to look at the terrorism angle" as a possible motive.
"We have not ruled out anything," he said. "We continue to look at all avenues, all motives."
Piro said Santiago was cooperating with investigators, who had interviewed him for several hours. The interview concluded early Saturday.
There were reports of a possible altercation involving Santiago on the flight to Fort Lauderdale, but law enforcement sources said investigators haven't discovered any evidence to support those claims.
The airline said it had received no reports of any incidents during the flight.
"Reports from customers and crew onboard the flight in question indicate that there was not a customer altercation during the flight," according to a Delta representative.
What was it like at the airport?
Sara Graham, who had been vacationing in Fort Lauderdale, wrote on Instagram that she and her family were about 100 feet away from the shooter.
Graham said her brother led her and her mother to safety after the commotion began.
"When we first heard the shots we had no idea what was happening until everyone started running towards exits," she wrote. "We hid for about 30 minutes and we're let back inside, under the impression it was all safe."
Then there was a rumor of another shooter and people started running again.
"Once we were outside, we had to run three more times until we were sure that we were safe," she said.
They spent the rest of Friday afternoon in an aircraft hangar before people were allowed to leave.
One of the shooter's bullets hit a laptop and ricocheted off, instead of hitting a man in the back.
One man told CNN's Anderson Cooper that a laptop in a backpack he had slung over his shoulder stopped a bullet that could have killed him.
"I felt something hit my back," Steve Frappier said, adding he thought it was luggage falling off the carousel.
It was a bullet, which ricocheted off the laptop. He found it in the side pocket of his bag.
Other witnesses described the aftermath of the shooting as a "war zone" and "mass hysteria."
What are rules for firearms in airports/checked bags?
Taking a gun on a plane is legal if a passenger brings the weapon in a case that locks and checks the suitcase containing the gun.
The gun cannot be loaded, though regulations allow travelers who fill out a declaration form to also bring ammunition.
Florida law prohibits guns inside terminals unless they are still in their case, but there is a bill before the state Legislature to allow guns in public places such as airports.
How was air traffic affected?
The Fort Lauderdale airport was closed for the rest of Friday, and more than 10,000 travelers had their trips interrupted for hours.
Flight tracking website FlightAware said 159 arrivals and 149 departures were canceled -- about a third of the scheduled flights.
The airport said services resumed Saturday.
Roads reopened Saturday morning for passengers and airport employees to reach the airport, according to its Twitter feed. Passengers were advised to check with their airline before traveling.
The airport said earlier it was collecting and processing more than 20,000 bags and personal items left behind during the evacuation to return them to their owners.
About 10,000 passengers were taken Friday by bus from the airport to a terminal at Port Everglades in Fort Lauderdale, officials said.
Some people were forced to remain on planes that landed but weren't allowed to reach their gates. One JetBlue passenger said he was stuck for six hours.
