UNION CITY, N.J. (CBSNewYork) -- Shocked relatives of alleged Fort Lauderdale airport gunman Esteban Santiago-Ruiz did not know what to make of the massacre Friday.
As CBS2's Jessica Moore reported, the FBI talked with Santiago-Ruiz's aunt and uncle -- Hernan and Maria Rivera -- in Union City Friday night. Police and the FBI were searching for anything that could possibly help them make sense of the senseless crime.
"May God have mercy on his soul," Maria Rivera said in Spanish.
Neighbors on 20th Street in Union City were also shocked.
"I was shocked. I couldn't believe it. I thought it was someone I didn't even know. You know what I mean?" said neighbor Felix Martinez. "Little did I know it was somebody that I knew. So it was just like, wow."
"They've got to be heartbroken," said neighbor Daniel Bayon. "I mean, I can only imagine what they're thinking."
Santiago-Ruiz was born in New Jersey, but spent most of his time in Puerto Rico before moving to Alaska.
There, he served with the Alaska army national guard until his discharge in August for "unsatisfactory performance."
Santiago-Ruiz spent nine years in the military, serving a tour of duty in Iraq. His brother, Bryan, told the Associated Press he was receiving psychological treatment. He questioned Saturday why his brother was allowed to keep his gun after U.S. authorities knew he'd become increasingly paranoid and was hearing voices.
When he told agents at an FBI field office his paranoid thoughts in November, he was evaluated for four days, then released without any follow-up medication or therapy.
"The FBI failed there," Bryan Santiago told The Associated Press. "We're not talking about someone who emerged from anonymity to do something like this."
Speaking in Spanish outside his family's house in Penuelas, the brother said: "The federal government already knew about this for months, they had been evaluating him for a while, but they didn't do anything."
Maria Rivera told NJ.com that her nephew "lost his mind" in Iraq.
Investigators said a fight with someone onboard that flight to Florida may have sparked the violence inside the airport.
Law enforcement sources told CBS News he traveled from Alaska to Minnesota and then from Minnesota to Florida. The second leg of the trip was on a Delta flight.
"There's not really much I can say any more about this. I'm just basically shocked," Martinez said. "That's all I can say."
"I mean, I do feel bad for them, and it's got to be crushing for their family to be going through something like this, you know, sort of crisis," Bayon added. "I mean, this is the type of thing that affects the whole family."
Agents questioned the Riveras for about 20 minutes before moving onto their next stop in what promises to be a long and emotional search for answers.
Five people were killed and six more were injured in the shooting at the Fort Lauderdale-Hollywood International Airport Friday afternoon. Santiago-Ruiz was taken in custody afterward.
Federal investigators say they have found no known links to terrorism, though FBI Miami Special-Agent-in-Charge George Piro said terrorism has not been ruled out.
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