"What did he know and when did he know it". The old Watergate cry. Congressional Democrats are in full cry on TV this morning. This is an accusation of thought crime. And I don't believe in thought crime. Liberty means the right to think anything you please. Crime has to be action of some sort.
The proper questions are "What did he do? When did he do it? Where did he do it? And what evidence do you have? " To be a crime it has to be an action. Thought (or knowledge) is never a crime.