The suspected gunman who opened fire Friday at Fort Lauderdale International Airport, killing five people, has been identified by officials as 26-year-old Esteban Santiago.

He was booked by the Broward County Sherriff's Office.

On Saturday, officials announced Santiago would face federal charges in the deadly shooting including killing five people, performing an act of violence against a person in an airport, and using a firearm in a crime.

According to the complaint, Santiago was "aiming at his victims' heads until he was out of ammunition."

If convicted, he could face a life sentence in prison.

Six more people were injured after the gunman opened fire around 1 p.m. at the airport, officials said. (An earlier injury toll of eight was revised down on Saturday to six).

"Indications are that he came here to carry out this horrific attack. We have not identified any triggers that would have caused this attack," FBI Special Agent in Charge George Piro told reporters Saturday, but added the "early indication is that there was no specific reason" as to why he chose Fort Lauderdale airport.

Piro said authorities have found no evidence of any altercation on a flight or in the terminal that might have prompted Santiago to open fire, but he cautioned that the investigation was still in its early stages.

The chief of the Anchorage airport police department told BuzzFeed News that Santiago arrived in Fort Lauderdale on a Delta flight, with his gun as his only checked luggage. Sen. Bill Nelson of Florida, who was first to identify Santiago, cited a military ID that was found on the gunman during his arrest.

The 26-year-old Anchorage resident was a member of the Alaska National Guard until August 2016 when he was discharged for "unsatisfactory performance," Lt. Col. Olmstead said in a statement.

Santiago began his military service when he joined the Puerto Rico National Guard in 2007 and was deployed to Iraq from April 2010 to February 2011, Olmstead said. Santiago was in the Army Reserves before joining the Alaska Army National Guard in November 2014 where he was a combat engineer. At the time of his discharge, he was a private first class.