Me. Rev. Stat. tit. 17-A, § 458

A person is guilty of retaliation against a witness, informant, victim or juror if, believing that another person is participating or has participated as a witness, informant, victim or juror in an official proceeding, as defined in section 451, subsection 5, paragraph A, or in an official criminal investigation, the actor engages in criminal conduct with the intent to retaliate for that other person's role in the official proceeding or official criminal investigation. Violation of this section is a Class C crime.