At the extreme, I suppose some DA or US Attorney might view the seizure as kidnapping and attempt prosecution, but I think that would be unlikely as it would be messy and be tied up in appeals for years with claims of official immunity.

FORBES: Wisconsin Dem. Senators Officially Fugitives From The Law

By contrast, the Obama executive order strips away those limitations, granting the international law enforcement agency blanket immunity from official and private efforts to assess its activities in the United States.

CENTERFORSECURITYPOLICY: Death by 1000 cuts

Lord Bingham concluded that a former head of state enjoys immunity as well because one English statute confers on a head of state the same legal protections as those enjoyed by an ambassador, which a second statute spells out as including immunity for official acts during his tenure as an ambassador even after he has left his post.

ECONOMIST: Bringing the general to justice