But to Suthamtewakul, Alexis seemed "frustrated with life."
She is grieving. "He was like one of our best friends, like a brother to us and always willing to go out of his way to help us out with things."
He was very frustrated with the company that contracted him to work for the Navy, according to another friend.
Alexis claimed he wasn't paid properly by the company after returning from a months-long assignment to Japan last year, said Michael Ritrovato, another former roommate.
It was unclear whether the dispute was over salary or expenses. Alexis just felt the company owed him money and had not paid him, Ritrovato said.
He is in shock over his friend's actions.
"He was an easygoing guy. I don't know of any reason for this," he said.
But Ritrovato knew Alexis was fascinated by guns. "He was ... knowledgeable with military rifles and handguns. At least he led us to believe he was. But nobody ever had the idea that he would use them in a derogatory way," he said.
It is not clear whether Alexis was still living in Fort Worth area at the time of the shooting.