Last Updated Jan 7, 2017 11:13 AM EST
FORT LAUDERDALE, Fla. -- Without a word, the gunman moved through the baggage claim picking off travelers until his handgun ran out of ammunition, leaving five dead and six wounded in Fort Lauderdale’s airport.
Panicked witnesses ran out of the terminal and spilled onto the tarmac, baggage in hand. Others hid in bathroom stalls or crouched behind cars or anything else they could find as police and paramedics rushed in Friday to help the wounded and establish whether there were any other gunmen.
Authorities said an Army veteran who complained that the government was controlling his mind drew a gun from his checked luggage on arrival and opened fire on fellow travelers.
Bruce Hugon, who had flown in from Indianapolis for a vacation, was at the baggage carousel when he heard four or five pops and saw everyone drop to the ground. He said a woman next to him tried to get up and was shot in the head.
“The guy must have been standing over me at one point. I could smell the gunpowder,” he said. “I thought I was about to feel a piercing pain or nothing at all because I would have been dead.”
The gunman was identified as 26-year-old Esteban Santiago of Anchorage, Alaska, who served in Iraq with the National Guard but was demoted and discharged last year for unsatisfactory performance. His brother said he had been receiving psychological treatment recently.
A U.S. law enforcement official briefed on the investigation told CBS News that Santiago had walked into the FBI office in Anchorage in November to say that his mind was being controlled by the CIA and the U.S. government and that he was being forced to watch videos from the Islamic State of Iraq and Syria, or ISIS.
Agents interviewed Santiago and then called police, who took him to a mental health facility. The FBI ran his name against the government database and found no connection to terror groups.
FBI agent George Piro, who is in charge of the Miami field office, confirmed that Santiago had come into the Anchorage office and said he clearly indicated at the time that he was not intent on hurting anyone.
Piro said authorities are looking at leads in several states and have not ruled out terrorism. “We’re looking at every angle, including the terrorism angle,” he said.
Santiago, who is in federal custody, will face federal charges and is expected to appear in court Monday, Piro said.
It is legal for airline passengers to travel with guns and ammunition as long as the firearms are put in a checked bag - not a carry-on - and are unloaded and locked in a hard-sided container. Guns must be declared to the airline at check-in.
Santiago arrived in Fort Lauderdale after taking off from Anchorage aboard a Delta flight Thursday night, checking only one piece of luggage - his gun, said Jesse Davis, police chief at the Anchorage airport.
At Fort Lauderdale, “after he claimed his bag, he went into the bathroom and loaded the gun and started shooting. We don’t know why,” said Chip LaMarca, a Broward County commissioner who was briefed by investigators.
The gunman was taken into custody after throwing his empty weapon down and lying spread-eagle on the ground, one witness said.
“Just shooting people that were ducked behind their baggage, underneath the chairs,” the witness, Mark Lea, told CBSN. “... People were yelling and screaming and frantically trying to get out of any door that they could or hide under chairs, hide behind their luggage or anything else to get out of the line of fire.”
Lea said the shooter was “calm as can be. He just walked in. He just started shooting. He wasn’t frantic, wasn’t psychotic.”
Lea said he was about 50 feet away from the gunman, who was carrying a 9 mm weapon. Lea estimated that the suspect shot about 24 rounds.
Lea said that after firing the shots, the gunman walked near a door, threw down his weapon and “laid spread-eagle on the floor down there and waited for the officer to come up and get him.”
The gunman was arrested unharmed, with no shots fired by law enforcement officers, and was being questioned by the FBI, Sheriff Scott Israel said.
Broward County Sheriff Scott Israel said 37 people were injured - scrapes, bruises and broken bones - after the shooting. On Saturday, Israel said six people were wounded from the shooting, not eight, which is the number authorities released on Friday. Three of the victims were in intensive care at a hospital, and three were in good condition, Israel said.
The condition of the wounded was not disclosed. At least one of the victims was seen lying in a pool of blood with what appeared to be a head wound.
The airport was shut down, with incoming flights diverted and outgoing flights held on the ground. CBS News correspondent David Begnaud reports that the airport reopened Saturday morning. Airport Director Mark Gale urged travelers to check with their individual airlines on flight status.
The bloodshed is likely to raise questions of whether aviation safety officials need to change the rules.
The attack also exposed another weak point in airport security: While travelers have to take off their shoes, put their carry-on luggage through X-ray machines and pass through metal detectors to reach the gates, many other sections of airports, such as ticket counters and baggage claim areas, are more lightly secured and more vulnerable to attack.
“The fact is that wherever there are crowds, such as at our airports, we remain vulnerable to these types of attacks,” Sen. Bill Nelson said.
President Obama was briefed by his homeland security adviser, the White House said. President-elect Donald Trump said that it is a “disgraceful situation that’s happening in our country and throughout the world” and that it was too soon to say whether it was a terrorist attack.
Santiago’s brother, Bryan, told The Associated Press that his brother had been receiving psychological treatment in Alaska. He said Santiago’s girlfriend alerted the family to the situation in recent months. Bryan Santiago said that he didn’t know what his brother was being treated for and that they never talked about it.
He said Esteban Santiago was born in New Jersey and moved to Puerto Rico when he was 2. He was sent to Iraq in 2010 and spent a year there with the 130th Engineer Battalion, according to Puerto Rico National Guard spokesman Maj. Paul Dahlen. He later joined the Alaska National Guard.
The Pentagon said Santiago had gone AWOL several times during his stint with the Alaska National Guard and was demoted - from specialist to private first class - and given a general discharge, which is lower than an honorable discharge.