First post, so I hope I don't mess this up, and I apologize for the length but I just wanted to get all the comments from my head into one place. I’ve been watching and reading (though unable to keep up it’s moving so fast). JMO: I do not think that this was an acquaintance who just got upset. I do not think this was just a jealous boyfriend. It takes more than fortitude to slaughter four people in this style. The fact that an obvious suspect has not been identified means that these murders are different than the norm, and today's pc didn't dissuade me from my opinion, but ICBW & hope I am.
I think this guy is a prepared thrill killer/serial guy who has been watching and waiting for a while. He may have left a lot of DNA from the victims and a bloody mess, but the “mess” seems to have been limited to the areas where the murders took place, not all over the house. Here are some thoughts and what may be a plausible scenario.
It’s not his first killing. Animals, of course, but (and this is only a guess), there is also at least one human victim prior to this. Those humans would may be those unlikely to be missed (homeless, prostitute, etc.), taken so that he could practice his trade unnoticed. Obvs in another town, maybe another state. This killing, though, I think he wanted to announce his presence to authorities, show how smart and skilled he is, esp if he didn't get enough notice before. Four people-that's brazen, that's a big calling card. Maybe that’s why LE (via the families, etc.) used the “made a mess” statement to bait him, hoping he'd respond. He’ll love all of the focus, but maybe irked by that “sloppy” remark, because (his thinking) if he’s so sloppy, why no footprints in and out? Why wasn’t there blood on the doors? How did he murder four people so easily and leave no obvious signs for the two he left alive?
He’d have watched, waited, practiced. From the wooded area behind the house at night, from social venues where he was able to unobtrusively follow these girls. On social media. He’d have eaten at the Mad Greek to see them in person. Paid cash, of course. He’d have done several recons to make sure he knew their patterns. He may have even been in the house when they were gone.
He’d have a full kit packed -a small, unobtrusive backpack. Shoe covers, maybe a buzz cut, but not totally shaved head and hair net w/double-sided wig tape to scalp so it couldn’t fall off, OVOS gloves, mask (don’t want to leave spittle). I think he’d go early and on foot for most or all of the way. He’d wait in the wooded area behind the house, prep there, not wait in the house, because of risk of discovery. Easier to get in while they’re asleep rather than get out if discovered while they were still awake. Getting caught for a B&E would ruin his future plans.
I think he’d have gone in through the second floor sliding door after he was sure everyone was asleep, not through the first door with the keypad, even though he might know their code. I believe the first floor only has one possible exit. He would not let himself be trapped. On the second floor, he would have three potential door exits. Even on the 3rd floor, more options and he’s in good shape, so he could jump from the third story window or deck, if needed.
He’d go to the second floor bedroom first. E, the biggest and potentially undesirable victim. He'd cut arteries & vocal chords. Even if E woke up and fought, it would not be for long. Same with X to silence her, but she fought back. He might even have pre-cut duct tape for over the mouths. The police are saying no one was bound and gagged, but did anyone ask about adhesive residue? Or tape left over the mouths?
After he finished, he’d have wipes in his kit to clean gloves, suit, etc. & he’d make sure he had everything counted. That’s why he practiced. He’d put on clean shoe covers he’d brought. Sounds dramatic, but maybe even a hazmat suit or fresh pullover. No need to leave a blood trail in the hall if he can help it. He’d lock the door as he goes out. He’d even use a wipe to open the door and shut it. Why leave a bloody print? He’s visualized this so many times mentally, he is relatively calm.
On the third floor, he knows no one will hear him. He can elaborate there. Possibly a quick piece of tape over the mouth. (I think this may be where he focused/targeted. I wonder if one was posed or displayed a certain way? Something to single her out? Maybe an outfit?)
I think he skipped the first floor roommates intentionally. Only one way out of there, too easy to get trapped. Four is enough, and leaving two alive bought him time. He doesn’t kill the dog. Wouldn’t be the first time a dog has been spared (eg: Meredith Emerson).
Car would be parked a reasonable distance away, but I think he'd find somewhere to wait & watch, if possible,walk to car in daylight. There’s nothing unusual about someone going to their car in broad daylight, so why draw unnecessary attention. Besides, if he watched, he’d get to see how this unfolds. If I were him, I’d know that LE would be looking for nighttime video. Daylight where no one clocks what they’ve seen would be smarter. Maybe a clean change of clothes hidden someplace?
The cops will investigate predictably (most obvious first), so he will have time to distance himself.
Everyone wonders why no one heard anything, but my thoughts: First floor is built into the ground, so silencing effect. Add in: Alcohol. Asleep. White noise machines. Headphones. And the ability to sleep through a lot when you live with four or five people. Sounds like no one saw blood in the hallways. The first floor roommates sleep late, so hours before they realize there is a problem, and once they do think there’s a problem, it’s not like they’ll suspect a murder right away. He’s got quite a few hours after dawn. Might have even left a camera or mic in the house. By the time LE start to put the pieces together, he will have moved on. I think that’s why the FBI BAU are on site - and called pretty early, too. Again, all just my opinion/imagination/too many movies/books.