Kevin Johnson, and Tom Vanden Brook

USA TODAY

Two months before Esteban Santiago allegedly unleashed a deadly assault inside the Fort Lauderdale-Hollywood International Airport, the 26-year-old former National Guardsman showed up unannounced – and troubled – at the Anchorage, Alaska offices of the FBI.

There, according to the FBI, Santiago told federal authorities that U.S. intelligence agencies had gained control of his mind and were urging him to fight for the Islamic State terror group. While the report was initially alarming, it was soon clear that the young man's reported complaint was more a cry for medical treatment than a matter meriting the attention of counter-terrorism officials.

"During the interview, Santiago appeared agitated and incoherent, and made disjointed statements,'' the FBI said in a statement Friday night. "Although Santiago stated that he did not wish to harm anyone, as a result of his erratic behavior, interviewing agents contacted local authorities who took custody of Santiago and transported him to a local medical facility for evaluation. The FBI closed its assessment of Santiago after conducting database reviews, inter-agency checks, and interviews of his family members.''

A background check, while revealing a brief military deployment to Iraq as a member of the Puerto Rico National Guard, found no nexus to terror.

Local Anchorage police authorities did not immediately respond to requests for comment.

Yet the troubling episode is now part of an emerging profile of a deeply disturbed man described by his aunt Friday as someone who had "lost his mind.''

Maria Luisa Ruiz of Union City, N.J., said her nephew, who had moved to Alaska for work as a security guard, only recently began to show signs of instability.

“Like a month ago, it was like he lost his mind,” she said “He said he saw things.”

Shortly after being informed that her nephew was a suspect in the stunning shooting that left five dead and eight others wounded, Ruiz showed reporters a photo taken in September of Santiago at a hospital holding his newborn son. Staff at Providence Hospital in Anchorage confirmed that the photo was taken in that hospital.

In the photo, the young father wore a T-shirt emblazoned with the logo for the band “Disturbed.” Ruiz said that Santiago, whose mother lives in Puerto Rico, appeared happy after the birth of his son, but that changed a short time later. She said he was hospitalized for two weeks, but she did not have details about his condition.

"I don't know why this happened,'' she said, before FBI agents showed up at her door and local authorities closed off the street near her home.

It was unclear whether Santiago, who was arrested without incident following the shooting, was cooperating with authorities. But by Friday afternoon investigators were engaged in a far-flung effort – from Alaska to Puerto Rico – to learn what drove the suspect to open fire in the baggage claim area of Fort Lauderdale's Terminal 2.

Santiago arrived in Florida early Friday afternoon aboard a Delta flight that originated Thursday in Anchorage and passed through Minneapolis, a federal law enforcement official said Friday.

The official said the suspect apparently retrieved a handgun from his checked luggage and loaded it before allegedly beginning the rampage in which victims were shot at random while they waited near a baggage carousel.

One passenger, Mark Lea, told MSNBC the man was "just randomly shooting people" without saying a word to anyone. After emptying about three magazines of bullets, the shooter then got down on the ground, spread-eagled and waited for police to arrive.

Sen. Bill Nelson, D-Fla., had initially identified the gunman, saying that he was carrying a military identification card.

Born in New Jersey, Esteban Santiago served in both the Puerto Rico National Guard and the Alaska Army National Guard, according to Lt. Col. Candis A. Olmstead, director of public affairs for the Alaska National Guard.

He joined the Puerto Rico National Guard in 2007, was deployed to Iraq from April 2010 to February 2011 and joined the Alaska Army National Guard in Nov. 2014. Santiago received a “general discharge” for unsatisfactory performance on Aug. 16, 2016.

The suspect's military record lists him as a "combat engineer," whose postings also included Fort Dix, N.J., and Fort Leonard Wood, Mo. He received an Army Commendation Medal, Army Good Conduct Medal and a Combat Action Badge.

Olmstead said Santiago was a “traditional soldier” in the Headquarters & Headquarters Troop 297th Cavalry in Fairbanks, Alaska, prior to his discharge.

Contributing: Keldy Ortiz, USA TODAY Network