[AC-Phoenix]

Originally Posted by Sute443

Or because Yoruko was right about the identity of the culprit, and Kains had just seen a ghost...

But seriously, if we're trying to solve the mystery, I think there are a few possibilities.

Spoiler for Speculation and saving space:

Possibility 1: Duels.
It's a distinct possibility that Yoruko accepted a duel to the death because of how guilty she was feeling, but Kains probably wouldn't have. He tried to pull the sword out of his chest, so he clearly wanted to live. It would probably have had to be some sort of duel exploit if he was killed in a duel. If it was a duel, it's possible that the killer has a high stealth item that prevented anyone from seeing him.

Possibility 2: Long range attacks from out of town.
Yoruko's death could have come from this, but not Kains' death. Even if the sword was thrown into his chest after he was tossed over the balcony, I have to think that tying a noose around someone's neck and throwing him out the window would be considered violent enough that normal rules wouldn't allow it. Not to mention, since someone was glimpsed near him on the ledge, it would require at least two culprits.

Possibility 3: There's a skill or item that breaks the safety of the inner area.
Not likely. Not only would it be unfair in the game, it would also be unfair in a murder mystery. If the answer is as simply as "The killer is allowed to break that rule," then that would just be a very unsatisfying answer to the mystery.

Possibility 4: A monster did it.
HIGHLY unlikely, but this is my favorite theory. The argument between Kirito and Asuna at the beginning of the episode implied that monsters are capable of hurting players even in villages, and the same might be true in cities. The idea is that someone lured a monster capable of using player-made items into the city and has enough control over it (maybe even like a beast tamer) to send it after people he wants to kill.

There is actually no proof she died - Most MMos have a fake death skill and I suppose she had it. its pretty much the easierst way to pull this cime off, especially since all impiortant information came from her.