Five people were killed, 6 injured in the shooting at the Fort Lauderdale International Airport. Photograph: (AFP)
If convicted of the charges Santiago could face the death penalty or life in prison, US Attorney Wifredo Ferrer said in a statement
Esteban Santiago, the 26-year-old gunman accused of killing five people after he went on a shooting rampage at an airport in Florida, may face the death penalty or life in prison, AFP reported.
FBI special agent George Piro said law enforcement was investigating motives for the attack, including "the terrorism angle."
The Iraq war veteran wounded six people and sent thousands scrambling for safety at the Fort Lauderdale International Airport before being taken into custody.
He has been charged with firearms offenses and carrying out an act of violence on Saturday, charges that could lead to a death penalty if convicted.
If convicted of the charges Santiago could face the death penalty or life in prison, US Attorney Wifredo Ferrer said in a statement. "Santiago started shooting, aiming at his victims' heads until he was out of ammunition," Ferrer said.
The suspect was scheduled to make an initial court appearance on Monday.
Santiago had traveled from Alaska to Fort Lauderdale on Friday. After retrieving a 9mm semi-automatic handgun and ammunition that he had declared and stowed inside his checked luggage, he allegedly loaded the weapon in a bathroom and opened fire in the crowded baggage claim area of Terminal 2.
He was detained without law enforcement having to fire any shots, Broward County Sheriff Scott Israel said.
The Fort Lauderdale airport was, meanwhile, open on Saturday and staff were trying to return nearly 20,000 pieces of luggage and other personal items abandoned by passengers fleeing the shooting, AFP reported.
A former member of the Puerto Rico and Alaska National Guard, Santiago served in Iraq from April 2010 to February 2011. He ended his service in August. He became father to a baby boy in September.
Suspect had mental health issues: Family
Santiago's aunt, Maria Luisa Ruiz, told the NorthJersey.com news site that he was having mental problems, AFP reported.
"Like a month ago, it was like he lost his mind," Ruiz said. "He said he saw things."
AFP quoted authorities as saying that on November 7, Santiago walked into the FBI's Anchorage office and complained that his mind was being controlled by national intelligence agencies, which were forcing him to watch Islamic State jihadist videos.
The "erratic behavior" led agents to contact local police, who took him to a medical facility for a mental health evaluation, FBI special agent Piro said.
He was not placed on a no-fly list.
Anchorage police chief Christopher Tolley said Santiago had come to the FBI office with a loaded magazine, but left his gun and newborn child in his car.
Santiago's weapon was taken by police for safekeeping at the time, and he was able to reclaim it on December 8.
Tolley said it was not known whether it was the same gun used in the rampage in Fort Lauderdale.
Santiago's brother, Bryan, criticized the way authorities handled his case.
"They had him hospitalized for four days and they let him go. How are you going to let someone leave a psychological center after four days when he said he hears voices that the CIA is telling him to join certain groups?" Bryan Santiago told CNN, in a Spanish-language interview the network translated into English.
"Not everyone has the same reaction when they return from war. Some are better, and some, not so much."
The shooting has renewed anxieties about airport security in the context of the ongoing US gun-control debates.
The Transportation Security Administration — the agency responsible for security at US airports — allows passengers to travel with unloaded firearms and ammunition as checked baggage.
Congresswoman Debbie Wasserman Schultz, who represents the Florida district that includes the airport, said the rules need to be reexamined.
She told CNN that the incident should prompt close review of "whether or not you should be allowed to check a firearm at all" — as well as how passengers should be able to retrieve checked weapons after landing.
"If there is still exposure to the traveling public of someone who wishes to do them harm and, like this individual, was reunited with their firearm and was able to wreak havoc... it absolutely needs to be addressed."
Senator Chris Murphy, a Democrat from Connecticut, rebuked the government for not taking legislative action to tighten gun laws.
"Political cowardice is the accomplice of every mass shooter," he wrote on Twitter.
(WION with inputs from AFP)