What is the scope of the powers of the grand jury?

"Traditionally the grand jury has been accorded wide latitude to inquire into violations of criminal law. No judge presides to monitor its proceedings. It deliberates in secret and may determine alone the course of its inquiry. The grand jury may compel the production of evidence or the testimony of witnesses as it considers appropriate, and its operation generally is unrestrained by the technical procedural and evidentiary rules governing the conduct of criminal trials. 'It is a grand inquest, a body with powers of investigation and inquisition, the scope of whose inquiries is not to be limited . . . by doubts whether any particular individual will be found properly subject to an accusation of crime.' Blair v. United States, 250 U.S. 273, 282 (39 S.Ct. 468, 471, 63 L.Ed. 979), (1919)."

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