If you know with certainty that the person knows the location of the bomb then you also know where the bomb is located.

It the same issue when the police and prosecutor know all facts with certainty. At this point you don't need a court, a judge or a jury. In an artificial system where everything is know with perfect certainty you don't even need police and prosecutors, just a method to punish the guilty. A legal system is only needed in order to determine who is guilty and who isn't, and this is unnecessary if we know already who is guilty.