Me. Rev. Stat. tit. 9-B, § 227

The superintendent shall have the power and authority to summon persons and subpoena witnesses, compel their attendance, require production of evidence, administer oaths and examine any person under oath in connection with any subject related to the supervision and regulation of financial institutions. Any summons or subpoena may be served by registered mail with return receipt. Powers granted under this section may be enforced by the Superior Court.