So important was its shield function that those protections were written into the Fifth Amendment of the U.S. Constitution. But legal experts say the federal grand jury today is often only a sword, acting as little more than a rubber stamp for prosecutors. In grand jury proceedings, prosecutors can call any witness, and the witnesses usually must testify. Witnesses cannot bring their attorneys into the room. No judge oversees the proceedings.
Grand jurors can question witnesses and often do.
Prosecutors can also present hearsay and other evidence that is normally inadmissible in court, such as evidence that may have been obtained illegally. Legal experts say it's very unusual for a grand jury not to return an indictment. The standard joke is that if a prosecutor asked, a grand jury would indict a ham sandwich. Still, legal experts and prosecutors say federal grand juries are essential to helping the government make complicated and sophisticated cases, such as those involving corruption, organized crime, and drug cartels, where witnesses are often reluctant to cooperate. Government prosecutors can also be extremely aggressive, he said, issuing subpoenas, for example, that require witnesses to show up with no notice.