Mont. Code Ann. § 46-30-404

A person brought into this state on or after waiver of extradition based on a criminal charge is not subject to service of personal process in civil actions arising out of the same facts as the criminal proceeding that the person is being or has been returned to answer until the person has been convicted in the criminal proceedings or, if acquitted, until the person has had reasonable opportunity to return to the state from which the person was extradited.