A few very important points that were not mentioned here:
First, no one, not the presiding judge, or the prosecutor tells the Grand Jury their rights or abilities before they embark on their journey as jurors, most of them do not ask questions let alone raise the Spector of asking for a Subpoena for more information the prosecutor forgot togive them….
Second, the Prosecutor brings in charges against the accused that he/she want the jury to bless or not bless with an indictment by giving them information and witnesses. The charges the prosecutor comes in with may have zero validity or basis in fact, but if the Jury does not catch on and indicts, the Prosecutor now has a hammer to negotiate a plea and avoid a trial with a bogus charge. How can this be, simple, there is no jeaoprody attached since the defendant cannot go to jail from a Grand Jury, making a false accusations to a Grand Jury is not considered Prosecutorial misconduct…welcome to the legal profession. An example is in order, my wife was an alternate juror and asked two questions to clarify a timeline[no one else had asked a question the entire day]. A husband and wife were accused of six felonies and 7 misdemeanors…those two questions took all the felonies off the table and 3 of the misdemeanors, by the time the Prosecutor and witness answered the questions. And you wonder why our prisons are full.
Grand juries are a place prosecutors take cases that are too weak to go directly to court, so they can use a secret proceeding where there are no defense attorneys allowed, where they can overcharge the accused to gain leverage, all while using uninformed citizens who are not aware of their rights and powers as jurors to do what they please despite what a judge implies to them….the jurors if they so pleased could take the investigation away from the prosecutor! But sadly it is the prosecutors show and he will generally as the saying goes indict his ham sandwich.
If Mueller had a case he would not need a Grande Jury, he would go directly to trial, its about intimidation.
The real question here is do the Grand Jurors have a clue how much power they have? The answer is no, since they will be intimidated since they are clueless as to their rights. Someone should be emailing them a copy of them. I know before I went to Jury duty I downloaded the entire manual and read it, and myself and another guy turned Voir Dire into Saturday Night Live. Even the judge was laughing. We asked more questions then the two attorneys! The real point is that Grand Juries are not needed if you have a good case.