The brother of the man suspected of carrying out the Fort Lauderdale airport shooting has questioned why Esteban Santiago was allowed to keep his gun after US authorities knew he had become increasingly paranoid and was hearing voices.
The 26-year-old reportedly had trouble controlling his anger after serving with the US National Guard in Iraq, and told his brother that he felt he was being chased and controlled by the CIA through secret online messages.
Speaking to FBI agents in Alaska, where he lived, Santiago had reportedly told them the government was forcing him to watch so-called Islamic State group videos.
When Santiago told agents at the FBI field office his paranoid thoughts in November, he was evaluated for four days, and then released without any follow-up medication or therapy.
"The FBI failed there," Bryan Santiago said, adding: "We're not talking about someone who emerged from anonymity to do something like this."
"The federal government already knew about this for months, they had been evaluating him for a while, but they didn't do anything."
The suspect in the Florida airport shooting chose to travel to Fort Lauderdale to carry out the attack which left five people dead, authorities have said.
The suspect "'came here specifically to carry out this horrific attack", George Piro, special agent in charge of the FBI's Miami office said.
Mr Piro added there were no signs of any altercation on board the flight or at baggage claim.
Mr Piro continued that Esteban Santiago, 26, the suspect, was cooperating with investigators and was interviewed for several hours overnight.
Six victims of the Fort Lauderdale airport shooting remain in hospital, Broward County Sheriff Scott Israel said.
Three of the victims remain in intensive care, he added.
While it was initially reported that eight people had been injured in the shooting as well as the five people who were killed, Sheriff Israel confirmed that six people rather than eight had been injured.
Fort Lauderdale airport has re-opened following a shooting on Friday which killed five people and injured eight others.
The gunman opened fire after he picked up his luggage at baggage reclaim at Terminal 2 of the Florida airport.
An operation is underway to reunite passengers who were evacuated from the airport in the wake of shooting with over 20,000 items of luggage.
#FLL is collecting and processing over 20,000 bags/personal items left from the evacuation. This is a time consuming and complex process.
A 26-year-old man suspected of carrying out the shooting has been named as Esteban Santiago and is currently in custody.
Santiago reportedly served in Iraq with the National Guard before he was discharged last year.
Images have been released of the man suspected of carrying out the Fort Lauderdale airport shooting, that left five people dead, after his arrest.
Esteban Santiago reportedly opened fire after he picked up his luggage at baggage reclaim at Terminal 2 of the Florida airport on Friday.
The 26-year-old reportedly served in Iraq with the National Guard, but was discharged last year.
Santiago had been receiving psychological treatment recently, according to his brother.
After being detained by police he was transported to the Broward County Main Jail.
The FBI has not ruled out terrorism as a motive for the Fort Lauderdale shooting, an official said.
Lead investigator for the FBI, George Piro, said the suspect Esteban Santiago will be charged federally.
"With these types of incidents, as horrific as they are, we are looking at all avenues, we have not ruled out terrorism and we will be pursuing every angle as we try to determine the motive behind this attack," he said.
Scott Israel, sheriff of Broward County, said that Santiago was taken into custody "without incident".
Five people died in the shooting and eight others were injured.
Up to 40 more people were treated for injuries after the incident including broken bones and strains, Israel said.
The suspected Florida airport gunman told the FBI in November that the government was controlling his mind and forcing him to watch Islamic State videos, a law enforcement official said.
The official, who spoke on condition of anonymity, told AP that agents in Anchorage completed their interview with 26-year-old Esteban Santiago-Ruiz and called the police, who took him for a mental health evaluation.
The FBI's Anchorage field office said in a statement that it was aware Santiago was an Anchorage resident and that it was assisting in the investigation, but it declined to comment further.
Police released a photo of a man suspected of carrying out the Fort Lauderdale airport shooting that left five people dead and injured eight.
Esteban Santiago-Ruiz, 26, reportedly opened fire after he picked up his luggage at baggage reclaim at Terminal 2 of the Florida airport.
A spokesman for US Senator Bill Nelson of Florida said he had a US military identification.
A US official told Reuters, on condition of anonymity, Santiago-Ruiz was honourably discharged from the Army National Guard last year and served in Iraq.
Chaos broke out at Florida's Fort Lauderdale airport on Friday when a gunman opened fire in a baggage reclaim area, killing five people and injuring 13 others.
Police say the attacker arrived on a flight with a gun in a checked in bag and after he claimed his luggage he went to the toilets and loaded the weapon, then emerged, shooting randomly.
ITV News correspondent Neil Connery reports:
The Canadian Embassy in Washington has said the gunman who opened fire at Florida's Fort Lauderdale airport on Friday was not on a Canadian flight and did not fly from Canada.
The update contradicts earlier comments made by a government official in Florida.
Citing US officials, Constantin said the suspect was on a flight that originated in Anchorage, Alaska and flew to Florida via Minneapolis.
Broward County commissioner Chip LaMarca earlier said the gunman had arrived on a Canadian flight with a gun in a checked bag.
"After he claimed his bag, he went into the bathroom and loaded the gun and started shooting. We don't know why," LaMarca said.