Maybe I’m wrong, but local law enforcement prevails over any other police action, including federal. We need a legal type to comment.
I believe the distinction is that if the icident (crime) happens on Federal property, the Feds have the jurisdiction, obviously...
If the crime or incident happens on local county/city property, it depends upon if the incident is a Federal crime...
For instance almost ALL plane crashes are Fedral since the NTSB is the lead on those incidents, and any Law Enforcement, in support of that investigation is lead by FBI types...Local/State act in a support role...
If the crime happens during a time of crisis, if the area is declared a disaster area, either Federally or by the State, then the lines get a little more intertwined, and agencies tend to se who can wiz up higher on the wall, until someone steps in and clearly defines who is the lead agency and who is supporting those lead elements...
But hey, in this case this is going to be a mess anyway you look at it...
All I can see is the fact that when the knocks on the doors occur, I just hope a lot of us get word of those encounters in time to go to general quarters and be ready to respond accordingly and proportionally to the threat...