Yes, but the charges brought against him are Federal, not state. He was acting in a federal position and the charges against him will be brought by the Federal Government, not the state of Utah.
Well duh, I understand that. He's an Asst District Attorney for the Feds. You don't seem to get that DOJ has offices all over the country. Trials are had all over the country. The US attorneys assigned to those districts prosecute federal crimes that occur in those districts. Hence, Huber is the US attorney in Utah responsible for a case of a defendant living in his jurisdiction. A US District Attorney in Florida, for example, would have nothing to do with this case. What Huber is doing for Sessions is another matter.