On one hand, putting the FBI on the case makes perfect sense - IF YOU REALLY WANT TO FIND THE KILLER. I wouldn’t trust the DE police forces to find anything.
OTOH, what better group than the FBI to cover up the crime - IF YOU REALLY DON’T WANT TO FIND THE KILLER.
I generally don’t think of coverups or government malfeasance - BUT this is the 0bambi administration and this action smells.
“putting the FBI on the case makes perfect sense -
...because it crossed state lines.