If the same act be a violation of two or more statutes, or of two or more ordinances, or of one or more statutes and also one or more ordinances, conviction under one of such statutes or ordinances shall be a bar to a prosecution or proceeding under the other or others. Furthermore, if the same act be a violation of both a state and a federal statute, a prosecution under the federal statute shall be a bar to a prosecution under the state statute. The provisions of this section shall not apply to any offense involving an act of terrorism as defined in § 18.2-46.4. For purposes of this section, a prosecution under a federal statute shall be deemed to be commenced once jeopardy has attached.