(Adds details on Santiago's court appearance)
By Zachary Fagenson
FORT LAUDERDALE, Fla., Jan 9 (Reuters) - The 26-year-old Iraq war veteran accused of killing five people at a busy Florida airport in the latest U.S. gun rampage appeared in a federal court on Monday on charges that could bring him the death penalty.
Esteban Santiago, who had a history of erratic behavior, was escorted into the courtroom near Fort Lauderdale for the brief hearing surrounded by U.S. marshals and wearing a red jail jumpsuit and shackles.
He has admitted to investigators that he planned Friday's attack at Fort Lauderdale-Hollywood International Airport and bought a one-way ticket from his home in Alaska to carry it out, according to a criminal complaint.
Authorities say they have not ruled out terrorism as a motive and that they are investigating whether mental illness played a role. In November, Santiago went to a Federal Bureau of Investigation office in Anchorage and told agents he believed U.S. spies were controlling his mind.
Santiago spoke little during the hearing, confirming to U.S. Magistrate Judge Alicia Valle that he understood the charges, and that he is a U.S. citizen. He said he did not have his own lawyer, and he was assigned a federal public defender.
Asked about his employment, Santiago said that for the last couple of years he had worked in Anchorage for a company called Signal 88 Security, earning about $2,000 per month. He told the court he had only $5 to $10 in his bank account.
Prosecutors called for Santiago, who is being held at the Broward County Jail in Fort Lauderdale, to be denied bail, and Valle scheduled a Jan. 17 hearing to discuss the request. Legal experts have said it is very unlikely he would be released.
"They've then got two weeks to indict him, and then they've got to go through the whole death penalty review," said former federal prosecutor David Weinstein, a partner with Miami law firm Clarke Silverglate.
Santiago could face the death penalty if convicted on charges that include carrying out violence at an airport and killing with a firearm. But it may be months before prosecutors reveal whether they will seek the death penalty.
Executions have been on hold in Florida since the U.S. Supreme Court struck down the state's death penalty laws a year ago. The Florida Supreme Court overturned a rewritten version in October.
Six people were wounded by gunshots in the attack, and three dozen suffered minor injuries in the chaos as passengers and airport workers fled.
Authorities say Santiago arrived on a connecting flight from Alaska and retrieved a 9mm semi-automatic handgun from his checked luggage before loading it in a bathroom.
He then returned to the baggage claim area and walked "while shooting in a methodical manner" 10 to 15 times, aiming at his victims' heads, according to the criminal complaint.
Information surfaced over the weekend that police in Alaska took a handgun from Santiago in November after he told FBI agents there his mind was being controlled by a U.S. intelligence agency. They returned it to him about a month later after a medical evaluation found he was not mentally ill.
Anchorage's police chief told reporters on Saturday that Santiago reported at the time having "terroristic thoughts" and believed he was being influenced by the Islamic State militant group.
Video published by the website TMZ on Sunday showed the gunman walking calmly past the airport's luggage carousels before pulling the handgun from his waistband and shooting at victims, who fled or dived to the floor.
Santiago served from 2007 to 2016 in the Puerto Rico and Alaska national guards, including a deployment to Iraq from 2010 to 2011, according to the Pentagon. Relatives have said he acted erratically since returning from Iraq.
The attack was the latest in a series of mass shootings in the United States. Some were inspired by Islamist militants, while others were carried out by loners or the mentally disturbed.
Reporting by Zachary Fagenson; Writing by Daniel Wallis; Editing by Lisa Von Ahn and Dan Grebler