Not sure your familiarity with bureaucracies - but if an underling let alone the Secretary of any organization is threatened, necessitating millions of dollars in security, there is a file somewhere.
And when it involves this much money, it is readily available . As in ---- on someones desk, top of the pile.
Or, conveniently hidden away in the David Dennison file
Death threats would likely go to the FBI.
That’s how bureaucracy actually works.