http://www.onlineupdatenews.com/2017/01/09/motive-of-florida-airport-killer-remains-a-mystery/
From the article above:
Neighbors in Anchorage say Santiago and his girlfriend were pleasant enough — until recently.
“We used to watch the mom sit on the front porch and watch her daughter play while she took care of the baby,” said Pamela VanDyke, whose back stairs and stoop face Santiago’s front door. “They seemed to be so happy.”
But in October some issues began to develop, said VanDyke’s daughter, Brittany Adams. She said Santiago started parking a space designated specifically for her mother because of knee and hip surgeries.
VanDyke and Adams said they tried to reason with Santiago, but he responded “rather darkly.” About two weeks ago a neighbor had to call the police because Santiago “was having a loud party and then kicked in his door,” Adams said.
“He just seemed to have more parties that got out of hand,” she said.
Didn’t the 9/11 Muslims party in the weeks before the attacks?