UPDATE 1:46 p.m. EST:
Santiago was ordered held without bond during a 15-minute hearing Monday afternoon. U.S. Magistrate Judge Alicia Valle said the death penalty could apply, which he said he understood.
Santiago said he only had $5 or $10 in the bank and made $2,100 a month working for an Alaskan security company.
More than a dozen officers kept watch outside the courthouse, carrying rifles and wearing bulletproof vests.
Esteban Santiago, the Army veteran accused of killing five people in a mass shooting at Fort Lauderdale-Hollywood International Airport on Friday, will appear in federal court Monday morning.
Santiago, 26, faces charges that could lead to the death penalty if convicted.
This hearing is likely to focus on ensuring Santiago has a lawyer and setting future court dates.
I want to ensure these families that law enforcement is working tirelessly in order to ensure justice is served.
The FBI agent who interrogated Saddam Hussein for months after his capture will lead the investigation into Santiago's shooting, according to the Associated Press. George Piro, 49, runs the FBI's Miami field office. Terrorism has not been ruled out in the investigation, but Prio said it's "way too early" to find any clear links.
GRAPHIC | TMZ posted video it claimed showed the initial moments of the shooting.
Who is Esteban Santiago?
Esteban Santiago-Ruiz, was born in New Jersey, lived in Alaska and Naples, Florida, and was discharged from the National Guard four months ago. He received a general discharge from the Alaska Army National Guard last year for unsatisfactory performance of his duties.
He had served as a member of the Puerto Rican National Guard for six years and served one-year overseas in combat in Iraq, according to family members who spoke with the media.
He talked about all the destruction and the killing of children.
The gun Santiago allegedly used in the shooting had been previously seized by police, CNN reports. His gun was taken after he went to an FBI office in Alaska, complaining that ISIS was controlling his mind. He got the gun back a month later.
Family members said his tour in Iraq changed Santiago.
WATCH | FBI officials said Santiago broke no laws during a visit when he came to the office, but did make comments about mind control. Officials also insisted Santiago worked alone.
The Associated Press and Circa's Sara A. Carter contributed to this report.