(CNN) -- Fort Lauderdale airport shooting suspect Esteban Santiago made his first court appearance Monday, during which Judge Alicia O. Valle advised him he would face three charges: performing an act of violence against a person at an airport serving international civil aviation that caused serious bodily injury; using and carrying a firearm during and in relation to a crime of violence; and causing the death of a person through the use of a firearm. Two of the charges carry a maximum sentence of death. Valle appointed Santiago a lawyer and set his next court date for January 17.
Esteban Santiago has already confessed to shooting up a Fort Lauderdale airport, authorities said, killing five people in the country's latest mass shooting.
But on Monday, he will appear in federal court for the first time to face three charges. If convicted of any one of them, Santiago, 26, could be sentenced to death.
Several new developments have surfaced about the attack, the victims and how the suspect may have "slipped through the cracks." Here's what we know:
The suspect's background and travels
-- Santiago, a security guard living in Alaska, had served in the US Army Reserve and the Alaska Army National Guard. He completed a 10-month tour of Iraq from 2010 to 2011.
-- After his time in Iraq, his aunt and brother said, he came back a changed man -- hearing voices or having "visions all the time."
-- Santiago recently began selling his possessions, including his car. Friends and associates noticed more erratic behavior, investigators have learned from interviews with those who know him.
-- Two months ago, Santiago voluntarily went into the Anchorage FBI office and said his mind was being controlled by US intelligence. He was "having terroristic thoughts and believed he was influenced by ISIS," Anchorage police said.
-- At that time, authorities took away his gun and ordered a mental health evaluation. But he was not deemed mentally defective, so authorities later gave him back his gun. Sources say it was the same gun Santiago used in Friday's rampage.
-- "We had this situation where he slipped through the cracks," CNN national security and law enforcement analyst Tom Fuentes said. But Karen Loeffler, the US Attorney for the District of Alaska, said she thinks "law enforcement acted within the laws that they have."
-- Santiago told investigators he bought a one-way ticket from Anchorage to Fort Lauderdale and brought a Walther 9-millimeter pistol and two magazines.
-- A lieutenant with the Anchorage airport police said Santiago had one checked bag -- a handgun case containing a pistol.
-- Santiago will be charged Monday with causing serious bodily injury to someone at an international airport; using a firearm during and in relation to a violent crime; and causing the death of a person through the use of a firearm.
-- Though authorities do not yet know Santiago's motive, the FBI has not ruled out terrorism.
Video of shooting released
Security footage obtained by TMZ shows the seconds before and after the shooting. The gunman walks through the baggage claim area at Fort Lauderdale-Hollywood International Airport, just steps behind a man and two boys, and pulls a handgun from his waistband.
The gunman then fires about three times before running out of the camera's view. A couple sitting nearby drops to the ground. A woman ducks behind a baggage cart. Several people, seeing nowhere to take cover, dive face-first to the ground.
After the deadly rampage, Santiago was arrested without incident, authorities said.
Four of the five slain victims have been publicly identified; two of them were grandparents.
Terry Andres was at the airport with his wife, about to start a vacation ahead of his 63rd birthday. His wife was not wounded.
"He and Ann were married for 40 years, and he absolutely adored his children and grandchildren," said a longtime friend who wanted to stay anonymous.
In the case of Michael Oehme's death, there were public condolences from state Sen. Chuck Grassley of Iowa.
"Pray as I will for Oehme family of CouncilBluffs Iowa /Father Michael was killed and Kari the mother was wounded at FtLauderdale Massacre," Grassley tweeted.
Shirley Timmons, 70, had been married for 51 years to her high school sweetheart, and "together they built a close, loving family with their three daughters, three son-in-laws and eight grandchildren," her grandson Steve Reineccius said in a statement. "For Shirley, family meant vacations, football games and holiday traditions."
Olga Woltering, 84, and her husband, Ralph headed to Fort Lauderdale for a cruise. Her husband was not seriously wounded.
"Olga was one of the most joyful, loving, caring and committed people I have ever met," the Rev. Fernando Molina-Restrepo of the Catholic Church of the Transfiguration in Marietta, Georgia, said.
Two of the injured victims remained in intensive care late Sunday, while the remaining four had been released or were recovering at Broward General Hospital, Sheriff Scott Israel said.
The hospital gave slightly different numbers, saying seven victims -- including five who had been shot -- remained hospitalized Sunday. One gunshot victim was released Saturday, the hospital said.
CNN's Evan Perez, Shimon Prokupecz, Ray Sanchez, Kevin Conlon, Sheena Jones and Pamela Brown contributed to this report.
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