While grand juries are sometimes described as performing accusatory and investigatory functions, the grand jury's principal function is to determine whether or not there is probable cause to believe that one or more persons committed a certain Federal offense within the venue of the district court. Thus, it has been said that a grand jury has but two functions—to indict or, in the alternative, to return a "no-bill." See Wright, Federal Practice and Procedure, Criminal Section 110.

At common law, a grand jury enjoyed a certain power to issue reports alleging non-criminal misconduct. A special grand jury impaneled under Title 18 U.S.C. § 3331 is authorized, on the basis of a criminal investigation (but not otherwise), to fashion a report, potentially for public release, concerning either organized crime conditions in the district or the non-criminal misconduct in office of appointed public officers or employees. This is discussed at JM 9-11.300 and JM 9-11.330. See Jenkins v. McKeithen, 395 U.S. 411, 430 (1969); Hannah v. Larche, 363 U.S. 420 (1960). Whether a regular grand jury enjoys a comparable authority to issue a report is a difficult and complex question. Cf. United States v. Briggs, 514 F.2d 794 (5th Cir. 1975). The Criminal Division of the Department of Justice should be consulted before any grand jury report is initiated, whether by a regular or special grand jury. See also JM 9-11.330.

[updated January 2020] [cited in JM 9-69.400]