Hunt the Dark Brotherhood

I have found the Dark Brotherhood's hideout in the ruins of Old Mournhold.

I have killed Dandras Vules, the leader of the Dark Brotherhood in Mournhold. As he died, he spoke to me. "Tell my liege I have failed...." Of whom Vules was speaking, I have yet to determine. Perhaps there is some evidence in his chambers that might lead me to the one who wishes me dead.

I've found a Dark Brotherhood contract that marks me for execution. The contract was written on the order of "H." This should give me some clue as to who wants me dead. I should report my findings to a guard immediately.