BREAKING: FL shooter allegedly told FBI in November he was being forced to fight for ISIS

The mass shooting suspect who allegedly pulled a firearm out of his checked luggage and killed five people in the Fort Lauderdale, Florida, airport apparently has ties to ISIS — at least in his own mind.

CBS News reported on Twitter that the shooter, Esteban Santiago, walked into an FBI office in Alaska several months ago and claimed he was being forced to fight for ISIS.

NEW: In Nov. 2016, FLL suspect walked into FBI office in Anchorage, claiming he was being forced to fight for ISIS, sources tell CBS News.

— CBS News (@CBSNews) January 6, 2017

NBC News said that Santiago was carrying military ID on him when he was arrested, and that friends and family both confirmed that Santiago had mental health issues. Sources also reported that Santiago was the subject of a child porn investigation about five years ago, but that no charges were filed.

Santiago's brother Bryan, who lives in Puerto Rico, spoke with NBC News Friday afternoon. He told reporters that Santiago served in the National Guard in Puerto Rico for six years, and also deployed to Iraq for a year. Santiago then served in the Alaska Army National Guard as a combat engineer, where he was discharged for unsatisfactory performance, according to KTUU. Santiago's aunt, Maria Luisa Ruiz, told reporters that Santiago was in the hospital two months ago.

"Something got to him. It looks like he lost his mind. He would say that he would see things. I don't know. So he went to the hospital. That's what I know. That's what the mother told me, who lives in Puerto Rico," Ruiz said.

As Santiago's story emerges, it remains unclear whether he actually had ties to or contact with ISIS, or whether his attempt to turn himself in to the FBI was merely a manifestation of the severe mental health issues described by family and friends. It remains possible that Santiago's true motive for his actions may never be fully understood.