We are continuing our discussion of grand juries, focusing, for the most part, on state and county grand juries. The rules for federal cases are different, most notably by virtue of the Fifth Amendment to the Constitution. If someone is accused of a federal felony (a capital or "otherwise infamous" crime), a grand jury must hand up an indictment before the case can proceed.
Here in Illinois, the decision is left to the prosecutor, who is not bound to explain why the grand jury was chosen instead of a preliminary hearing with a judge presiding. Some legal commentators believe that grand juries tend to indict, regardless of whether the evidence is convincing. Others suggest that a grand jury indictment sounds better to the media. Whatever the reason, it is the prosecutor's decision.
The grand jury is made up of 16 citizens, all residents of the county or counties that the panel serves. While trial juries will serve for one trial, each member of the grand jury may hear as many cases as are scheduled during his or her service.
Another important difference between a trial jury and a grand jury: The grand jury actively inquires into the matter before it. The trial jury weighs the evidence but does not question witnesses or direct the prosecution to conduct further investigation.
The grand jury only reviews information submitted by the prosecution, but it may also order an investigation without the direction or involvement of the prosecution. The jurors themselves will not do the investigating, though -- that only happens in the movies. Rather, the grand jury appoints an investigator (or investigators). If the investigation calls for witnesses or documents to be subpoenaed, the grand jury has that power.
When the grand jury is satisfied that it has enough information to make a decision about probable cause (a relatively low bar), the jurors will vote on whether to indict the accused. The vote need not be unanimous. If an indictment is handed up, the "accused" officially becomes the "defendant," and the trial proceeds.
All grand jury proceedings are held in the strictest secrecy. Witnesses will not hear the testimony of other witnesses. The jury's deliberation and vote are held in secret, too. The law does allow that testimony may be shared under certain circumstances.
It is possible to challenge a grand jury's indictment. It is also possible for the prosecutor to present the same case to a different grand jury. So, the decision carries weight but perhaps less than the public believes.
Regardless of perceived flaws in the process, someone who is called to testify must take the matter seriously. Rather than go it alone, though, most witnesses consult with an attorney before they testify.
Source: Illinois Courts, Grand Jury Handbook, accessed online Dec. 18, 2015