I wonder if the decision to drop the "murder for hire" charges was originally influenced by his existing life sentence, and whether the pardon now alters that reasoning. Is it still possible for him to be prosecuted on those charges?
I think they were dismissed with prejudice, which if true, is a “no”. That said, all prior charges and attempts were federal charges, and nothing in a pardon or federal dismissal prevents an individual state from bringing charges, IIRC. Would be a heavy lift though without cooperation from feds to turn over investigation materials.
