A "US spook" is not a "mid-level person". Nor does a "US spook" have the authority to make the swedish government issue a warrant. Nor is a "US spook" above the law. It is within the means of an American intelligence agency, or military, of course, but the decision would come from and be authorized from the highest levels of command.

That being said, it would be an idiotic way of dealing with this situation. It smacks of amateurism, and while I may have qualms with what american intelligence agencies do, they are very good at what they do, and certainly not amateurs.