So then, it's alright for us to discuss theories I'd assume. No requests, but let's talk about the clues here.
@Krein seemed to be operating on a suspicion that the thief who got away before never actually got away, and was in fact an employee. I have already stated my suspicion of the maid; I believe that she may have been angered at being left nothing in the will, since she was not among the parties mentioned. It is also possible that she was in fact the thief, as she was the only one to spot the mysterious figure. Krein also seemed to follow my thinking; the valuables may have been stashed in the wine barrels, and retrieved, though the Red Truths seem to be against that idea. It bears further thought, though. The cleaning rag spotted in the room with the will was what made me think of the maid, but it could possibly have been one of the other suspect's.