A Secret Room Quest
After you have eavesdropped the killers’ dialog, examine two rooms which are located next to each other. There are two statues inside. Interacting with each of them will lower or raise swords. Besides, if you touch one statue, other statues will be activated. It happens in a certain order that you should identify on your own. It’s very easy to do.
Then you need to use the following combination: swords on all statues should be directed upwards. In this case, in the lower room a passageway to a secret room with a chest containing a ring and weapons will appear.