Actually, she is avoiding the arm of US justice like the plague. That is why she spouts her propaganda from Berlin. They are so busted.
You indicate why she does not want to come into the USA now. That does not explain AT ALL why Mueller has ignored her.
In fact, to the extent that she may have any criminal jeopardy in the USA, that makes my point even more strongly that Mueller & co. are irresponsible and incompetent at best.... or they are actively avoiding certain lines of investigation.