Looking for random public input about unusual behavior and situational context at both the bar area and the frat house suggests that LE remains pretty well in the dark as to motive and/or whether there was one intended target.
This is why I feel it was random, serial-esque, and that the 'target' was all four of them. That, and they all were asleep according to the coroner. That means no disagreement/escalation on site. No evident disagreement/escalation at either of the places that each pair were (I'm sure as many attendees as possible have been exhaustively interviewed to this effect). No persistent stalker. No fight. No rage. No waking up and stumbling onto a crime in progress. This was methodical and efficient, and as "gruesome" and "messy" and "sloppy" as the scene was, according to sources, it doesn't appear the killer left a lot of himself behind.
My opinion.