Me. Stat. tit. 5 § 199
The Attorney General shall consult with and advise the district attorneys in matters relating to their duties. If in the Attorney General's judgment the public interest so requires, the Attorney General shall assist them by attending the grand jury in the examination of a case in which the accused is charged with treason or murder, and if in the Attorney General's judgment the public interest so requires, the Attorney General shall appear for the State in the trial of indictments for treason or murder. The Attorney General may institute and conduct prosecutions for all offenses against Title 21-A, and for that purpose attend and present evidence to grand juries and assist them in the examination of witnesses and drawing indictments. The Attorney General may, in the Attorney General's discretion, act in place of or with the district attorneys, or any of them, in instituting and conducting prosecutions for crime, and is invested, for that purpose, with all the rights, powers and privileges of each and all of them. Any or all of the powers and duties enumerated in this chapter may, at the discretion of the Attorney General, be delegated to and performed by, any deputy attorney general, assistant attorney general or staff attorney. The authority given under this section shall not be construed to deny or limit the duty and authority of the Attorney General as heretofore authorized, either by statute or under the common law. [1989, c. 502, Pt. A, §11(AMD).]
5 M.R.S. § 199