Hi all, long time lurker, first time poster.
Just a couple of thoughts that I'd like to share. First of all, if any specific person was targeted the surely there must have been "better" (i.e. safer from the perps point of view) opportunities to attack that person when he or she is separated from friends or other people who may fight back. If it was a planned attack then why "plan" on going into a house full of people? Surely there are way better plans than that. Next, in my opinion there is no way (considering the staircase, movable stuff and dog running around) that the perp didn't use any sort of light amplification hardware. Surely at 3-4 AM the inside of the house would be pitch black and hard to navigate even if the perp was familiar with the layout, things get moved, young people ofter rearrange space around them. Finally, if it there was any sort of planning going into this attack and the perp was absolutely decided on using a knife then, again, surely he'd realize that it's hard to subdue two people fighting for life with just a bladed weapon. Back in the old days Zodiac, who definitely planned a lot, and was also boind on using a knife during one of his attacks, knew that it's safer to simply approach victims openly with a firearm, order to lay face down, tie them and only then attack with a knife knowing that they're immobilized. After all, what guarantee did King Street perp had that *all* of the house occupants are asleep and/or heavily inebriated. So potentially one loud scream and he'd have 6 people awake and fighting for life (or, more likely) running away. Only an idiot wouldn't have a firearm as a backup for "crowd control" in such situation.
So, while this doesn't seem to me like a work of a psychopath high on drugs (he had to be silent to a degree, didn't leave the weapon on site, wasn't spotted in bloodied clothes etc.) there also doesn't seem to be an evil mastermind behind it (using knife instead of gun, selected extremely risky venue).
And finally, I don't think the victims were completely unaware that some sort of attack may take place. I seems to me that multiple attempts to contact ex that night by one (or even both) of the girls would indicate they were trying to reach out for help. So this makes going into this house woth jist a knife, no matter how large, even more risky. Just the fact that the lighs are switched off doesn't always mean that everyone's soundly asleep instead of just laying awake with a handgun, taser or can of pepper spray close by...
Sorry for a lenghty post, all of the above IMHO.