Here's what we know about the suspect:
The gunman was identified as 26-year-old Esteban Santiago of Anchorage, Alaska, who served in Iraq with the National Guard but was demoted and discharged last year for unsatisfactory performance. His brother said he had been receiving psychological treatment recently.
"Only thing I could tell you was when he came out of Iraq, he wasn't feeling too good," his uncle, Hernan Rivera, told The Record newspaper.
NEW JERSEY CONNECTION:
Santiago was born in New Jersey, but a state official said he apparently hasn't lived in New Jersey for "quite some time."
FBI agents arrived at his aunt's house in Union City Friday afternoon to interview her. Interviews with family members is standard procedure after a mass shooting.
Here's an image showing the street, shut down by Union City police:
MILITARY AND JOB HISTORY
He has a recent address listed in Anchorage, Alaska. There, he worked for a company called Signal 88 in a security capacity, according to a source familiar with the investigation.
A law enforcement official told The Associated Press that Santiago had walked into the FBI office in Anchorage in November to say that the U.S. government was controlling his mind and making him watch Islamic State videos.
Agents questioned an agitated and disjointed-sounding Santiago and then called police, who took him for a mental health evaluation, according to the official, who was not authorized to discuss the case and spoke on condition of anonymity. The official said Santiago did not appear intent on hurting anyone.
Contacted for comment, a person who answered the phone at Signal 88 in Anchorage said, "We are currently under the advisement of federal authorities and we have no comment."
Lt. Col. Candis Olmstead, Director of Public Affairs from the Alaska National Guard, confirmed these details:
- Joined the Puerto Rico National Guard Dec. 14, 2007
- Deployed to Iraq with Puerto Rico National Guard April 23, 2010 to February 19, 2011
- Was in the Army Reserves prior to joining the Alaska Army National Guard Nov. 21, 2014
- Received a general discharge from the Alaska Army National Guard Aug. 16, 2016 for unsatisfactory performance
- He was a combat engineer (MOS: 21B10)
- When he was discharged, his military rank was E3 (Private First Class)
He received these awards for his time in the service:
- Army Commendation Medal
- Army Good Conduct Medal
- National Defense Service Medal
- Iraq Campaign Medal with campaign star
- Global War on Terrorism Service Medal
- Armed Forces Reserve Medal w/ "M" Device Army Service Ribbon Overseas Service Ribbon Combat Action Badge Driver and Mechanic Badge - Wheeled Vehicle
The Fort Lauderdale mayor told reporters the shooter was a "lone gunman" and didn't appear to be working with anyone else.
HOW HE ARRIVED AT FLL:
Law enforcement officials said Santiago boarded a plane Thursday night in Anchorage, changed planes in Minneapolis and flew to Fort Lauderdale Friday.
Once he got off the plane, officials said he claimed his checked baggage containing a gun, went into a restroom and came out shooting.
A person at the airport took this photo of a gun on the ground, but it's not clear if it was the gun the shooter used.
Officials said Santiago was arrested after he apparently ran out of ammunition at the airport. He was lying down at the terminal when he was taken into custody.
He was not injured during the incident, and is being interviewed by detectives.
Stay with Action News and 6abc.com for all the updates.