Before a defendant can be made to face trial for committing a felony, there has to be “probable cause” to believe that, first, a crime was committed, and second, the defendant committed it. Probable cause means trustworthy information that would make a reasonable person believe the defendant committed the crime. In Arizona, whether or not there is probable cause can be decided two ways: (1) by a judge after a preliminary hearing on a criminal complaint; or (2) by a grand jury on a bill of indictment. The prosecutor decides which of these methods to use.
A preliminary hearing is usually held in justice court. Both the prosecutor and the defendant are at the hearing, and the defendant usually has a lawyer. First the prosecutor puts on evidence through a few witnesses, usually police officers, to show probable cause, and the evidence may include “reliable hearsay.” Reliable hearsay is information that a witness got from other trustworthy people, instead of through the witness’s own experience. The defendant has the right to question these witnesses. When the prosecutor is finished, the judge decides if there is probable cause. If there is and the defendant says he can disprove it, the judge can let the defendant testify or put on witnesses. The prosecutor can question these witnesses. If at the end of the hearing the judge decides there is probable cause to believe the defendant committed the charge in the complaint, then the prosecutor files a document called an Information in the superior court and the case is set for trial. If the judge does not find probable cause, then the complaint is dismissed and the defendant is released if he or she is in custody. The prosecutor can still file another complaint with more evidence or different charges, or present the case to the grand jury instead. Preliminary hearings are public and have public records.
On the other hand, the grand jury proceeds in secret until an Indictment is filed. In fact, it is a crime for anyone to say anything about what happened during a grand jury proceeding. This is to protect witnesses from intimidation and the defendant’s reputation in case he or she is not charged. Just like trial jurors, people get summoned by the court to serve as grand jurors. The grand jury’s job is to investigate public offenses, and each member must promise to be fair and not prejudiced. The prosecutor gives the grand jury a paper called a “bill” with criminal charges against the defendant, and explains all the laws that the grand jury should apply in deciding whether there is probable cause to believe the defendant committed those crimes. Just like a preliminary hearing, the prosecutor then presents evidence to the grand jury through a few witnesses, often using reliable hearsay. Unlike a preliminary hearing, there is no judge and neither the defendant nor his or her lawyer is allowed to be there or to question the witnesses. The grand jury can let the defendant testify if the defendant asks in advance, but does not have to. The grand jury can also decide to call more witnesses, including the defendant, if it wants more evidence. The grand jury decides whether there is probable cause by a vote of at least 9 out of 12 jurors. If the majority decides there is probable cause, then the grand jury presents the prosecutor a true bill of indictment. The Indictment is then filed in the superior court, and the case is set for trial. If there is no bill of indictment, then there are no formal charges and the defendant is released if he or she is in custody. The prosecutor can try again with more evidence or different charges, or can file a criminal complaint and ask for a preliminary hearing.
For more information, see: