Michigan Compiled Laws, Chapters 760 to 777 Code of Criminal Procedure § 767.7d

(a) 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.

(b) 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.