US website release video of Florida airport shooting suspect pulling gun in front of shocked passengers
Warning: Graphic scenes
Video of the suspect in the Fort Lauderdale airport rampage calmly drawing a pistol and opening fire in the baggage claim area has been released by a US website.
The recording posted on TMZ's website appears to show Esteban Santiago at the airport on Friday, pulling a handgun from his waistband and then firing several times before running.
Santiago, 26, is accused of killing five travellers and wounding six others in the attack.
He was charged on Saturday with an act of violence at an international airport resulting in death - which carries a maximum punishment of execution - and weapons charges.
His first court hearing is on Monday.
The FBI said it was aware of the video but would not comment on its authenticity. TMZ did not say where it obtained the footage, although it appears to be from a surveillance camera.
Santiago told investigators that he planned the attack, buying a one-way ticket to the Fort Lauderdale airport, a federal complaint said.
The authorities do not know why he chose his target and have not ruled out terrorism.
The authorities said on Saturday that they had interviewed roughly 175 people, including a lengthy interrogation with a co-operative Santiago, who is a former National Guard soldier from Alaska.
FBI Agent George Piro said Santiago spoke to investigators for several hours after he opened fire with a 9mm semi-automatic handgun that he appears to have legally checked on a flight from Alaska.
"Indications are that he came here to carry out this horrific attack," Mr Piro said.
"We have not identified any triggers that would have caused this attack. We're pursuing all angles on what prompted him to carry out this horrific attack."
Investigators are combing through social media and other information to determine Santiago's motive, and it is too early to say whether terrorism played a role, Mr Piro said.
In November, Santiago had walked into an FBI field office in Alaska saying the US government was controlling his mind and forcing him to watch Islamic State group videos.
Santiago had been discharged from the National Guard last year after being demoted for unsatisfactory performance.
Santiago had requested psychological help but received little assistance, his brother Bryan said on Saturday. Esteban had told him in August that he was hearing voices.
Bryan Santiago said: "How is it possible that the federal government knows, they hospitalise him for only four days, and then give him his weapon back?"
His mother declined to comment as she stood inside the screen door of the family home in Puerto Rico, wiping tears from her eyes.
The only thing she said was that Esteban Santiago had been tremendously affected by seeing a bomb explode next to two of his friends when he was around 18 years old while serving in Iraq.