OP here. The other roommates are not suspects. It's not been said if they're male or female, but it's assumed they're female from everything else that has been said. The 4 victims absolutely were all killed inside the house. That is certain. The Police have repeatedly said evidence at the scene makes them believe it was a targeted attack, but they will not divulge the details on why they think that. They are also not saying whether the victims were all together or in separate rooms, but I assume they were in separate rooms, partly because it's a tri level house with 2 rooms on each floor, and partly because I think it's unlikely one guy would take on 4 people at once. Everything suggests all 4 victims were asleep, and the perp killed them in their sleep, I'm guessing by something like a slashing to the neck since there was apparently little noise. The scene inside has been described as very complicated...
Also, drugs are not believed to be involved at all, definitely nothing like a drug deal or anything like that. The perp is likely white since almost everyone in Moscow is white.
There was a separate incident in September where someone on campus flashed a knife at a group of people and threatened them, but nothing really has been made of that in connection to this event. The police have not said anything about it, and when it was asked about during the press conference, it was talked about like it was a nothing thing, something that happened and was resolved (the guy apparently turned himself in and explained the verbal altercation).
In the Twitch video, there is a guy seen that kind of hovers behind the girls just standing there watching them, then he starts following them as soon as they start to leave. It's impossible to say if there's anything to that, but it does look very suspicious. I would imagine tracking down that guy would be high on the list.
Again, absolutely horrible tragedy, and such a strange case. Probably gonna be a Netflix documentary on it in a year or two. It would be nice if people could be respectful while discussing this btw. Four families just lost a loved one in a brutal murder, and these kids were 20-21 years old just living their lives. Let's try to be mindful of that.