Hello WS. First time posting. I found the site through a search and I've several pages of this thread and this seems like a tactful group, which is important when discussing such a shocking and horrible crime. I'd like to see if I can add to the discussion and learn a bit.
Couple of my early thoughts, going from the assumption that there was a single murderer:
1. This was not an easy crime to commit and to be able to leave the scene completely undetected, which is what seems to have occurred.
a. The scene had to be approached unnoticed.
b. Entry had to be undetected.
c. The killer had to move to the victims, possibly having to locate them, possibly in the dark, and enter their rooms, silently.
d. Each victim had to be killed fairlly quickly and silently, with a knife, in whatever sleeping position they were in. The killer had to do this four times.
e. After the last murder, the murder had to exit silently, especially if he/she knew there were still people alive.
f. Then the kiler had to leave the vicinity unnoticed.
2. It seems unlikely, to me, that anyone in these undergrads' circle of friends would be capable of carrying out this crime. I don't think this is a whodunit among the student body, nor do I think this was a crime of passion.
3. I don't think, at this point, that there is any meaningful connection between these four students and their killer. This may have been targeted, with the victims, or location, having been selected some time prior.
4. It would not surprise me if this is not the first time this killer has killed a person, with a knife. This was a brazen crime, seemingly carried out with confidence.