Grand juries can be convened, pursuant to 18 United States Code §3331, if a representative of the Attorney General's office writes a letter to the chief U.S. District Court judge. The plaintiff, Ronald Patterson, was unhappy with the results of prior litigation and filed a petition for a writ of mandamus, to order the U.S. Attorney to conduct a grand jury investigation. 18 U.S.C. §3331 provides, "In addition to such other grand juries as shall be called from time to time, each district court which is located in a judicial district containing more than four million inhabitants or in which the Attorney General, the Deputy Attorney General, the Associate Attorney General, or any designated Assistant Attorney General, certifies in writing to the chief judge of the district that in his judgment a special grand jury is necessary because of criminal activity in the district shall order a special grand jury to be summoned." The plaintiff did not provide any evidence that the chief judge received a letter from the Attorney General. When courts force the government to initiate a criminal prosecution, there are separation of powers concerns. "Even if the court had discretion to convene such a grand jury, which it does not," wrote the District Court, "it would decline to do so given the absence of evidence of criminal wrongdoing, and the myriad institutional interests implicated." The District Court reminded the plaintiff that he possesses the option to appeal and that pursuit of similar requests to the District Court could result in sanctions. 

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