Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

The Iraq war veteran accused of killing five people in a Florida airport appeared in court Monday and was told he could face the death penalty.

Esteban Santiago gave brief yes or no answers to a federal judge who sought make sure he understood the charges against him, according to The Associated Press.

Santiago, 26, who was dressed in a red jumpsuit, said he did.

Related: Fort Lauderdale Shooting: Shocking New Video Shows Moment Rampage Began

He also provided some background about himself, including that he'd most recently worked as a security guard in Anchorage, Alaska, and only had $5 to $10 in the bank. He owns no property and doesn't have a car, he said.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

The case against Santiago is likely to include questions about his mental health.

Related: Gun Used by Airport Shooting Suspect Was Once Taken Away From Him — Then Returned

Two months before his Friday shooting spree, Santiago walked into an Alaska FBI office with his infant child "to report that his mind was being controlled by a U.S. intelligence agency, the special agent in charge there told reporters on Saturday. He said he was having terroristic thoughts and believed he was being influenced by ISIS, police added.

Relatives have said they feared Santiago's 10 months in Iraq with the Puerto Rico had impaired his mental health.

At the FBI office, officers confiscated a gun from Santiago car.

His brother, Bryan Santiago, told Telemundo that he was taken by police for a mental health evaluation and was released after four days.

Records also show the Santiago had been arrested in January 2016 for assault and criminal mischief after a violent argument with his girlfriend in Anchorage.

Related: Fort Lauderdale Shooting: Three Victims Were Headed to Vacations

A few weeks after walking into the Anchorage FBI office, he got the gun back. Authorities now believe he used that same gun, a Walther 9mm pistol, to open fire in the baggage claim area of Terminal 2 at Fort Lauderdale-Hollywood International Airport, killing five and wounding six.

Santiago opened his attack after flying from Anchorage overnight, with a connection in Minneapolis, checking his gun and ammunition in a gun box, authorities said.

He has been charged with performing an act of violence against a person at an airport serving international civil aviation and two other counts.