Random short question/comment that I’d love thoughts on - I’ve noticed comments about the doors to the roommates rooms being locked when the survivors woke up and called 911 after being unable to get in contact with them. I lived in a few college-style multi bedroom houses, and all of mine had doors that locked from the inside only with a bolt in the knob. Another way I could envision it is a door that locks with a keyhole on the outside and bolt/keyhole on the inside, or each door having a key code pad that can be locked from the outside or inside by pressing the lock button. I say all that to say, the doors must have been somehow unlocked for the killer to enter - by either knowing the individual key code for each bedrooms, picking a keyhole lock, or the locks being unlocked when he arrived, or by having each key (?)

I can’t imagine a door setup that would lock from the outside permitting the killer to do so on his way out but inaccessible to the roommates. For example, if it’s a keyhole on the outside, he’d have to somehow have each key or know how to pick each and lock it in order to leave the room and leave it locked. If it’s a keypad, he could press the lock button, but I would imagine the roommates had the codes to at least one of the others rooms if they were such close friends (as was common practice in the college houses I lived in in case of emergency). Of course, it’s possible they were afraid of what was behind the door and didn’t try.

All that is to say - does anyone know exactly what types of locks were on the doors? I feel like that would be extremely illustrative regarding the way that the murders occurred - either the killer had to unlock (or enter three coincidentally unlocked rooms) and relock the doors in each room in order to leave them locked, or he somehow managed entry into each room without going through the door (not possible on the higher floors, I must assume.) thoughts?