The man who is suspected of gunning down at least 13 people at Fort Lauderdale airport, killing five, has been named as a 26-year-old US citizen Esteban Santiago.
The suspect, who is unharmed and in federal custody, reportedly told the FBI in November that he was hearing voices in his head, that the government "controlled his mind" and "forced" him to watch Isis videos.
He was also being prosecuted for domestic violence, after he threatened his girlfriend through a door last January, broke through it and strangled her, as reported by The Daily Beast.
Santiago was detained at the baggage area at terminal two at the Florida airport on Friday afternoon shortly after he allegedly opened fire, randomly shooting people in the head.
His brother, Bryan Santiago, told the Associated Press that the suspect was receiving psychological treatment in Alaska, where he was living, and the family was alerted to this after receiving a call from his girlfriend.
Bryan Santiago said he did not know what kind of treatment it was and had never talked to his brother about it.
US senator Bill Nelson said the suspect was carrying a military identification at the airport, but it was not clear whether the ID was still current.
The suspect was born in New Jersey and moved to Puerto Rico when he was two years old.
He served in the island's National Guard and spent a year serving in Iraq in 2010 in the 130th Engineer Battalion. During his time there, he was awarded the Combat Action Badge as a driver and mechanic.
Santiago was honourably discharged from the Alaska Army National Guard in August 2016, almost two years after joining. He previously served in the US Army Reserves.
On the day of the mass shooting, and contrary to previous reports, the suspect was not on a flight from Canada.
It is believed that he instead flew from Anchorage in Alaska via Minneapolis, according to Canadian Embassy spokeswoman Christine Constantin. There he changed there to another Delta flight to Fort Lauderdale.
Witnesses said the gunman was involved in an altercation during the flight, but the incident was not serious enough for him to be stopped when the plane landed.
When he landed at Fort Lauderdale, he is said to have retrieved his weapon from his checked bag, loaded his weapon in the bathroom and then opened fire in the baggage terminal, saying nothing as he shot randomly at passengers.
He was reportedly apprehended by police when he had stopped to reload his gun and was taken into custody "without incident".
Authorities did not comment on what weapon he used, apart from that it was a semi-automatic handgun.
They told reporters they were at the “early stages of the investigation” and were yet to identify the deceased or notify their relatives as of 10pm local time.
Law enforcement officials told CNN that Santiago had showed up at the FBI office in Anchorage in November. He was interviewed and said he was hearing voices, including some telling him to join Isis.
He was taken into custody by local police and taken to hospital. He voluntarily checked himself in to hospital for a mental health evaluation. The FBI looked into his "contacts" but then closed the investigation.
Santiago's domestic violence case was ongoing. He violated the terms of his release after he was arrested last January when he turned up at his former partner's house and that case is still pending. The assault case was resolved in March when lawyers in Anchorage deferred prosecution in return for the completion of certain requirements which are unknown.
The FBI said they would pursue "every angle imaginable" and he would most likely face charges.
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