Originally Posted by TK-421
My guess is that it'd be treated like private property, the local LEOs are not allowed in the post office for official duty unless they're invited in.
But if you consider a post office to be federal property, then I'd call your local FBI office, ....
Actually the question might be better asked of either the US Postal Inspection Service or the US Postal Police rather then the FBI.
And in a huge, perhaps majority of situations, local LEOs absolutely do not need an invitation to enforce laws on private property. In fact one of the laws that is sporadically enforced on private property in this state is Obstruction of Justice FSS 843, which well more than once, has found someone seated handcuffed in the back of a Criwn Vic or Monaco or a couple models in between (and possibly before) when they mistakenly thought they could deny the police entry.
But I digress from the topic at hand.
Here is a good treatise on jurisdiction on federal property.
And with due respect to Ms. Solari and Mr. Perry it seems in practice at least sometimes the Postal Service allows concurrent jurisdiction.