This country has this odd system of "Due Process".  

You don't get to lock someone up unless and until they are actually charged with a crime.  And you don't get to keep them locked up until and unless they are found guilty a specific provable crime beyond a reasonable doubt.

That did not happen after any of the three FBI 'interviews'.  

If the FBI comes to your house and interviews you about something you said about your neighbor, does that mean that gives them the right to lock you up for three years?

That is what you are advocating here.