Earlier quoted context omitted.
I'm curious how you would construct a switch that couldnt be bypassed by the police once they have full access to the servers.
A dead man's switch could wipe the server and all backups to erase evidence. The police in this case let the server run for months to catch other sellers. A well hidden software trigger would have been hard for the police to notice without a thorough inspection of all the source code.
A dead man's switch can't wipe the server and all backups, imaging the machine is the first thing one does (before e.g. attempting to log in); the only thing that may vary if you dump the machine with or without turning it off, e.g. getting a memory image by direct hardware access of a live system or imaging disks (and possibly RAM as well, the chips can be read if they're cooled and re-inserted quickly) after cutting the power.