Empty reserves

Exploration Stage: Artifact Bank
From: Mr. Black
Description: We need to check out the safe that Broderick bought. Even if it's against the rules, the safety of the city is paramount. We need to know what kind of artifact the man is interested in. The man may have made a questionable transaction. Can you help me with that?
Completed: Surprise. Broderick's safe is open and empty. Only a few small talismans remain inside. The man took all the artifacts he had deposited in the bank. Did he decide to use all of them? But for what?