When is a grand jury used?

When ever they want to.

In Michigan a grand jury is rarely used but could be used. It is always used in the federal system. As to when various states use a grand jury, you would have to look at each state's statutes.

Ok, here's the process. You're arrested and charged with a crime. You're case now goes to District Court. If your crime is a misdemeanor, then it can be resolved by a guilty plea or a bench trial (a trial before the judge - no jury) in District Court. Felony trials are not done in District Court, but they can take guilty pleas on felonies. So if you're charged with a felony, you can plead guilty in District Court. If you don't want to plead guilty, you'll have a date set for a preliminary hearing in District Court. This is just a hearing to see if there is "probable cause" to continue prosecuting the crime. Sometimes your attorney will want to go through the actual hearing, and sometimes he'll just waive the hearing. After this hearing date, the case is sent to the grand jury. The grand jury is a group of citizens that decide if there is enough evidence to support "probable cause" to continue the prosecution. Since the only people allowed to testify to the grand jury are the prosecution's witnesses, there is almost always an indictment ( a finding that there is probable cause) - hence the saying "you can indict a ham sandwich." After the grand jury comes back with an indictment, the case is given a new case number and a setting in Circuit Court, where felony jury trials can be held. So the grand jury isn't really a choice of how the prosecutor proceeds, it's just a step in the criminal justice system.

Grand Juries are used as a matter of course in Federal Courts and they are called in special circumstances in State courts.

Grand juries are used when the prosecution does not have enough evidence to convince a judge that the subject should be held to answer for a crime. It is also used when the prosecution is trying to charge more than two subjects. In a grand jury the jury only hears one side, the prosecutions side. The defendant is not allowed to present any evidence or cross examine the witnesses. The defendant is not allowed to be present and cannot be represented at the grand jury hearing. This lowers the bar so much that the prosecution almost always gets an indictment.

Very good question. All federal cases begin with a grand jury so most states have at least a federal grand jury. The law allows that criminal cases can begin with an indictment by a grand jury however many states have elected to use a complaint system instead of using grand juries. In California at least 98% of all criminal cases begin with the prosecutor filing a complaint instead of a grand jury indictment. When a case begins with a complaint instead of an indictment, defendants are entitled to an extra level of protection. They get a preliminary hearing within ten days of being arrested if they do not waive time. In California grand juries are used to perform a complete different function. They are used by counties to investigate and make recommendations about things like county spending and county practices. They can actually be very powerful because their power to investigate is nearly limitless. In rare situations a prosecutor may request a special grand jury to hear evidence and return a criminal indictment. Sometimes prosecutors use indictments for political reasons. For example, there may be a very influential person that is accused of a crime. The prosecutor can avoid risking potential political backlash for filing a complaint against someone if they end up not being convicted. I had a case once a few years ago where the prosecutor obtained an indictment because the three defendants were masters at dragging a case out. After four years of trying to do a preliminary hearing the D.A.'s office obtained an indictment and skipped the preliminary hearing all together.

A Grand Jury is used in every state of the US. It consists of 16-21 people and it is used as a screening instrument when the prosecutor is about to charge someone with a felony. In fact, in order to be formally charged with a felony, every felony case must go before a Grand Jury to make sure there is reason to believe a felony has been committed and there is reason to believe that the subject of the presentment actually committed the felony. Good luck.

All felonies require indictment by a grand jury in NH. Felonies can be started by complaints in district court, but only bind a person to the superior court.

I would guess without knowing for sure that each state (and the feds) have grand juries. Why do they use them: It lets them avoid a preliminary hearing so they don't have to lay out part of their case. The feds do it in virtually every case. California rarely does it. In 46 years I have had about 5 cases go to the grand jury. Another reason (and I am doing this case right now) is that there are 10 defendants involved in various aspects of a marijuana grow some are connected and some are not. The DA, who really doesn't understand the case, would like to get a grand jury indictment and hope she can pressure some of these guys to plead.

I believe that they do have grand juries in all states. A grand jury is used to lodge felony charges. A defendant can waive his or her right to be indicted by a grand jury.

No, they do not have grand juries in all states. Each state has its own requirements for calling a grand jury.