TAMPA - "He's a good guy. You know, from what I know," said a former Texas roommate.
The people who knew Aaron Alexis, who thought they were close to him, still can't believe he had it in him.
"It's so night and day to me right now. It's just. It's not even in his character," said friend Melinda Downs.
"There's no question he would have kept shooting," said D.C. Police Chief Cathy Lanier.
Now the FBI is investigating what motivated Alexis, a former military man who served from May 2007 to January 2011 at a Naval station in Fort Worth, Texas, to commit mass murder.
"Mr. Alexis had legitimate access to the Navy yard," said a Washington, D.C. investigator.
Friends say Alexis was a practicing Buddhist but was obsessed with military-style video games. They also say he was frustrated with contract work after a recent japan trip.
Now the FBI investigation is turning up other substantial clues .
Alexis worked as a civilian computer contractor and had secret security clearance to work on sensitive systems in the D.C. Navy yard. Investigators searched his rental car and hotel room. They also interviewed his parents in New York City.
"You start with the individual and you work outward and then you work even further outward," said retired FBI profiler Joe Navarro.
Navarro now lives in the Tampa Bay area.
"The investigation starts very quickly and literally hundreds if not thousands of people are immediately called out. Usually what happens is you're told within 3 hours, locate everybody that this individual has ever associated with, worked with, gone to school with and that's really the best way to do a post-psychological post-mortem on this individual," he explained.
Navarro says the FBI will look into character and personality flaws and triggers that may have ignited these psychological tears.
"They're going to talk to everybody that ever worked with him. They're going to go all the way back to grade school and talk to the children he grew up with," he said.
Despite all the investigation may turn up, Navarro says we still may never know why Alexis resorted to a violent rampage.
"For investigators, it's we've long ago learned that it's not so much the why for us but rather finding out what were all the events that led up to this because you can never predict with 100-percent accuracy what will be the trigger for any single human being," he said.