Mich. Comp. Laws § 767.7d: Grand jury convened by court of appeals; circumstances.

Sec. 7d.

The court of appeals may convene a grand jury under section 7c with jurisdiction over 2 or more counties in this state if a petition is properly filed under section 7b, and all of the following circumstances exist:

The petition establishes probable cause to believe that a crime, or a portion of that crime, has been committed in 2 or more of the counties named in the petition.

The petition establishes reason to believe that a grand jury with jurisdiction over 2 or more of the counties named in the petition could more effectively address the criminal activity referred to in the petition than could a grand jury with jurisdiction over 1 of those counties.