Oh my god. I… I just wish that I could give more likes. This is the best answer I’ve ever seen, and I think will ever see. I’ll even elevate it to a Red Truth, just not the one for this murder.
In an alternate universe, this was how the murder was committed.The culprit for the basement murders was not human. The two victims found in the basement had planned to fake their deaths, and thus they faked the stakes in their head. The real “stakes” referred in the red could’ve been the beast’s teeth, which tore off as it viciously devoured its victims. How had the beast entered? It burst through the glass of the closed and locked window. The window was thus open - after all, there was a giant hole in it - but undeniably closed and locked at the same time, as well as unusable. The beast then exited through a dog door in the door. It is not a secret passage, it is part of the door. The door is indeed locked, so there are no contradictions. The dog then went upstairs and killed Dalinar, who snuck into the guesthouse as the others were entering. This explains all of the murders and doesn’t, as far as I know, contradict any of the red. The bodies in this case were indeed the five stated in red. They were all victims or witnesses. The beast was indeed inside the room when it killed everyone. It was not let in. The beast - this dog - was mentioned in the story. After all, luaDOG had promised he was the one who’d killed “these” people (possibly referring to the people in the basement) before the story had even begun.
Sadly, it’s not the correct answer, although I REALLY want it to be.