Well, there are plenty of reasons a US Marshal might be in a state courthouse. To testify as a witness, to escort a witness or defendant who is in federal custody, to serve a federal or interstate warrant, or to assist local law enforcement on some matter. He may even be there because Kenosha is anticipating civil unrest after the verdict and the US Marshals are one federal entity that can be called to assist with civil unrest, like we saw Trump do in 2020.
Sure. Any news reports on the feds being on hand? No. If a US Marshal happened to be in the building, and I’d suggest that is a relatively rare occurrence in a state courthouse, how would he become privy to what would be tightly held info. Info that even the bailiff in charge of the jury should not be privy to. The answer is he wouldn’t. The article specifically says a US Marshal and I’m sticking by my BS call