As a California resident facing a federal criminal charge, you may face a trial jury, grand jury or both. While both types of juries include jurors selected for jury duty, those jurors serve different purposes, and their decisions have different implications.
According to the U.S. Courts, a grand jury reviews details presented by a U.S. attorney and then decides if the evidence provided is sufficient enough to warrant a criminal trial. A trial jury, or a “petit jury,” on the other hand, determines if you actually committed the offense in question. There are other important differences between the two jury types, too.
The main job of the grand jury is to figure out if there is “probable cause” to believe you committed the federal offense you face. These juries typically have between 16 and 23 members, and their proceedings remain private. You do not make an appearance before the grand jury, and neither does your lawyer. If the grand jury finds that probable cause exists, it then issues an indictment against you.
A trial jury has somewhere between six and 12 members. While the jury trial, itself, is public, jury deliberations are not. You have the right to appear and testify in front of a trial jury, and you may also have witnesses testify on your behalf. The trial jury then determines if you are guilty or not guilty of the federal offense with which authorities charged you.
While these are some of the key distinctions between grand juries and trial juries, this is not an exhaustive summary of how the two jury types differ.