I think this is the federal charge. There has to be a way to assume federal jurisdiction and that is through the federal kidnapping statute. The states have jurisdiction over murders within their borders, but the federal government doesn't have such jurisdiction unless there is some nexus to them, like murder of a federal agent, kidnapping across state lines, etc. If the state prosecutes, undoubtedly it will be first degree.
If the Feds try it I doubt they will seek the death penalty. That would be a miscarriage of justice in my layman's opinion