A prosecutor can file a criminal complaint directly against someone, which initiates a case. But in some states and the federal system, when dealing with felony crimes, a prosecutor must present the charges to a grand jury, which will then decide whether probable cause exists to support the charges. If the grand jury decides the charges have merit, it issues an indictment.
Both an indictment and a complaint are court pleadings that begin a criminal case against someone. The difference between them centers on how they originate.
An arrest alone does not signify the beginning of a criminal case. (In fact, an arrest might not occur until much later in the process.) Typically, though, the police forward an arrest report to the prosecutor, and the prosecutor decides whether to pursue criminal charges. A prosecutor can generally do this in one of two ways, depending on the laws in the state.
In some states and the federal system, the law requires prosecutors to submit charges to the grand jury system and those charges take the form of an indictment. In other states, the prosecutor files a criminal complaint directly against the defendant. The relevant law determines which option the prosecutor must use. Although, in many places, the prosecutor can choose whether to file a complaint or go before a grand jury to pursue an indictment.
In order to get an indictment, a prosecutor must present evidence to a grand jury—a panel of citizens selected for duty just like a petit (or trial) jury. Grand jury proceedings are secret and a one-sided affair, with only the prosecutor presenting evidence. The grand jury reviews the evidence to determine whether it's likely that the accused committed the crime (a probable cause standard). If a majority (or the required number) of grand jurors agree probable cause exists, it votes to indict. If it decides the evidence doesn't support the charges, no indictment results and no charges are filed at that time. Learn more about the process in What Is a Grand Jury?
Sometimes people confuse an indictment with a conviction. While both are serious, they are very different. An indictment from a grand jury happens at the beginning of a case and signals that the defendant is facing criminal charges. To indict, the grand jury must find it likely that the defendant committed the crime. A conviction, on the other hand, occurs near the end of a criminal case and results from a defendant pleading guilty, accepting a plea deal, or being found guilty by a petit jury. In order for a petit jury to find someone guilty, they must decide unanimously that the defendant committed the crime beyond a reasonable doubt, a much higher standard of evidence than the probable cause standard that a grand jury uses to accuse someone.
An indictment contains notice of the criminal charges against an individual. After a grand jury indicts someone, it returns the indictment to the court and the criminal case begins. If the suspect (now-defendant) isn't already in custody (jail), the defendant may be arrested or summoned to appear before the court for preliminary hearings.
The case will then proceed to trial within a set time frame which can vary depending on the jurisdiction. In federal court, the time period is 70 days, but states have varying timelines. The trial must happen within that time frame unless the defendant chooses to waive his or her right to a speedy trial or accepts a plea deal. (18 U.S.C. § 3161 (2020).)
If you are facing charges based on a grand jury's indictment, it's important to speak to a criminal defense lawyer as soon as possible about your rights and the criminal process. Decisions made early in the process can have a big impact on the final outcome of the case.