"The only box someone could find is the one in the front, that needs to be public. We have multiple of those, scattered like diarrhea around the world. They contain no storage device, no graphics card. Only a network cable, a cpu and memory."

Interesting. So if these servers are seized and turned off you don't know where they were talking to. Though if the police are careful they ought to be able to tap the outgoing connections and get the IPs for the others servers they were communicating with and go from there.