There are many steps that occur in a criminal case. Some of these only happen in some cases and not others. One of these is the grand jury process. When the grand jury reviews a case, they are trying to determine whether there is enough evidence to warrant a criminal trial. If they find that there is, they will issue an indictment. The prosecutor can choose to abide by that indictment and bring charges or they can decline to follow the indictment and not press charges.
Not all cases are handled through a grand jury. Federal cases that are felonies must go through the grand jury. It is up to each state to determine which cases must be handled in this manner. The rules of the specific court system will apply to the grand jury proceedings if they are used.
Typically, grand jury hearings aren't as strict as a criminal trial hearing. This is because the grand jury isn't actually deciding on the fate of the person. In fact, grand jury hearings are confidential, so people who are involved can speak freely.
One point to remember is that if the grand jury issues an indictment, the indictment might not be able to be released right away. These are sometimes held in confidence until the person is arrested so that the person doesn't have time to try to flee from justice.
If you find out that you have been indicted on any criminal matter, be sure that you get your defense started right away. This gives you time to consider the options and move forward with planning your strategy.