I still think the killer was acquainted with at least one or more of the victims, possibly knew or knew of everyone who lived in that house, and had some familiarity with the house. I believe he laid in wait and watched the house that night. From what vantage point and for how long, Idk — obviously. MOO.
If he was watching and waiting from the outside, he would’ve known that exactly 6 people were home at or near 2:00 am. If the killer was fueled by rage at at least one target, his murderous impulse must have reached no-going-back threshold for him to risk entering a house with 6 people. MOO.
I can see hiding in wait inside if the killer had one female target and was delusional enough to think he could commit one isolated murder without confronting or disturbing 5 other people and quietly slip away into the night. Otoh, if he’s waiting inside the house, he has no idea how many people are going to roll in. From the outside, he at least would’ve known if 4-5 stragglers were in tow needing a place to crash. After all, it’s a large multi-level party house on a busy college weekend. Does he enter a house with 10 college students not knowing if 3 of them are stone cold sober? MOO.
That’s more or less my general theory, and even that is on a wide spectrum. I’d need a spreadsheet or flow chart to even begin to sort out the various gradations of possibilities and eventualities, particularly as to the killer’s motive, state of mind, and extent and nature of relationship to victim (real or imagined?) All MOO and too exhausting to fully contemplate.
Beyond that, there’s the psychopath serial killer passing through town or a more local random psychopath. What theories am I overlooking?
No matter what, there’s definitely a cold-blooded killer on the loose. Not just anybody commits a quadruple homicide by stabbing.
All of the above is MOO.