The takeaway is that if you are going to argue that X group is dangerous because they will commit Y act, you cannot use a lack of Y as weak evidence that X exists, because then Y would be strong evidence that X does not exist, and Y is what you are afraid X is going to do!
You would be much better off using the fact that no sabotage occurred as weak evidence that the 5th column was preventing sabotage.
If there is other evidence that suggests the 5th column exists and that they are dangerous, that is the evidence that should be used. Making up non-evidence (which is actually counter evidence) is not the way to go about it. There are ways of handling court cases that must remain confidential (though it would certainly make the court look bad, it is the right way to do it).
The takeaway is that if you are going to argue that X group is dangerous because they will commit Y act, you cannot use a lack of Y as weak evidence that X exists, because then Y would be strong evidence that X does not exist, and Y is what you are afraid X is going to do!
You would be much better off using the fact that no sabotage occurred as weak evidence that the 5th column was preventing sabotage.
If there is other evidence that suggests the 5th column exists and that they are dangerous, that is the evidence that should be used. Making up non-evidence (which is actually counter evidence) is not the way to go about it. There are ways of handling court cases that must remain confidential (though it would certainly make the court look bad, it is the right way to do it).