LOL! I'm still betting on Muslim convert (although he may also have been a nut or had a personal grudge, such as rejection by a girlfriend), because of the beard and the skullcap, if those reports were accurate. Furthermore, the family has two sons, and this would be the one, I believe, who was going to college in OK, although I don't know what school.
Clearly you've never known a lot of college guys. Most guys I knew in college grew a beard at least at one point in their college careers - myself included.