(1) A person is guilty of custodial interference when, knowing that he has no legal right to do so, he takes, entices or keeps from lawful custody any mentally disabled or other person entrusted by authority of law to the custody of another person or to an institution.
(2) It is a defense to custodial interference that the person taken from lawful custody was returned by the defendant voluntarily and before arrest or the issuance of a warrant for arrest.
(3) Custodial interference is a Class D felony unless the person taken from lawful custody is returned voluntarily by the defendant.