I honestly don't know what to think. I do not believe that college-age young men are less likely to commit crimes against young women; they are probably the most likely, if we had the stats. Even if the person is not one of the current POI's, he could well be another college student, as the population of that area seems to be almost completely college students and those awake and out at the hour might well be college students. Lots of young men have rage issues or a short fuse, and no one really knows to what degree until it is too late.
I do think the fight is a factor, at least for now. Lauren may not have been "involved" but she may have been the reason. No one would want to admit to that once she is missing, but I believe it was related.