You don't start with a lawsuit in the case of a this kind of theft. You hope the FBI or some other law enforcement/criminal investigators can track down and pr

You don't start with a lawsuit in the case of a this kind of theft. You hope the FBI or some other law enforcement/criminal investigators can track down and prove the guilt of the thieves. Jumping to the question of "who do I sue" implies that you want to get money out of someone not directly involved in the crime. In the example of gold in a safe, the question might be "can I sue the safe company to try to recoup some of my loss, even though it wasn't their fault that my opsec was shit?". If there exists no explicit legal agreement that was violated (e.g. the bank that promised to secure your gold was robbed) then you're just being an overly litigious asshole acting in a way that will make our entire society weaker and more vulnerable.