What Is a Grand Jury?

A grand jury is a group of ordinary citizens convened by a court to decide whether there is enough evidence to formally charge someone with a crime. Unlike a trial jury — sometimes called a "petit jury" — a grand jury does not decide guilt or innocence. It decides whether a criminal case should move forward at all. If a grand jury finds sufficient evidence, it issues a document called an indictment. Understanding how grand juries work, and what rights you have, matters whether you are following a case in the news or have received a subpoena yourself.

The Constitutional Basis

The Fifth Amendment to the U.S. Constitution provides that no person shall be held to answer for a "capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury." This means that in federal criminal cases, the government generally must obtain a grand jury indictment before prosecuting someone for a serious offense.

However, the Fifth Amendment's grand jury requirement applies only to the federal government, not to the states. States are constitutionally free to use grand juries, preliminary hearings, or prosecutor-filed "informations" (formal charging documents filed without grand jury involvement) to initiate serious criminal cases. Many states use grand juries regularly for felony charges; others use them rarely or only in specific circumstances such as cases involving public officials. The procedures, requirements, and when grand juries are used vary significantly from state to state.

How a Grand Jury Works

A grand jury is made up of ordinary citizens selected through a process similar to trial jury selection, though the exact number of jurors and how they are chosen vary by jurisdiction. Grand juries typically serve for a set term and hear multiple cases during that period, rather than just one case like a trial jury.

For any individual case, the process generally unfolds like this:

• The prosecutor presents evidence. The prosecutor presents witnesses and documents to the grand jury. This presentation is one-sided — there is no defense attorney in the grand jury room arguing against the charges. Grand jurors can ask questions of witnesses and request additional evidence.
• The proceeding is secret. Grand jury proceedings are not open to the public. Witnesses are typically sworn to secrecy about what they testified to. This secrecy protects the integrity of the investigation, protects witnesses from retaliation, and protects the reputation of people who are investigated but not ultimately charged.
• The standard is probable cause. The grand jury only needs to find probable cause — a reasonable basis to believe a crime was committed and that this person likely committed it. This is substantially lower than the proof beyond a reasonable doubt required to convict at trial.
• The grand jury votes. If enough grand jurors agree there is probable cause, they issue a "true bill," which becomes an indictment and formally charges the person. If they find insufficient evidence, they return a "no bill" and no charges are filed — though prosecutors may be able to re-present evidence at a later time in some circumstances.

Grand Jury vs. Preliminary Hearing

Both a grand jury and a preliminary hearing serve the same fundamental purpose: testing whether there is enough evidence to subject someone to the full burden of a criminal trial before doing so. The key practical differences are:

• Who decides: Grand jury — citizens decide. Preliminary hearing — a judge decides.
• Whether it is public: Grand jury proceedings are secret. Preliminary hearings are typically open.
• Whether the defense participates: No defense attorney is present in the grand jury room. At a preliminary hearing, the defense can cross-examine witnesses.
• Evidence rules: Grand juries routinely receive hearsay and other evidence that would be excluded at trial. Preliminary hearings are somewhat more formal.

Which process applies in your situation depends on whether you are in federal or state court, which state you are in, and what the charges involve.

Rights of Grand Jury Witnesses and Targets

If you receive a grand jury subpoena — a legal order to testify or to produce documents — you generally must comply or risk being held in contempt of court. However, your rights in the grand jury room are specific and important:

• Right against self-incrimination. Under the Fifth Amendment, you have the right not to answer questions that might incriminate you. You can "take the Fifth" in the grand jury room and refuse to answer specific questions on that basis.
• No right to have your attorney in the room. Unlike most legal proceedings, your lawyer cannot sit with you inside the grand jury room while you testify. However, you can pause, leave the room, and consult with your attorney in the hallway before answering questions. This is an important right — use it whenever you are uncertain about a question.
• Target, subject, or witness status. Prosecutors typically distinguish between a "target" (someone they believe committed the crime and whom they are building a case against), a "subject" (someone whose conduct falls within the scope of the investigation), and a "witness" (a third party with relevant information but not believed to be a perpetrator). Your status affects your risk, but it can change over the course of an investigation. If you receive a grand jury subpoena, consulting a lawyer immediately before appearing is critical regardless of what you are told your status is.
• Immunity. In some cases, prosecutors may offer a witness immunity from prosecution in exchange for testimony. There are different types of immunity, and their scope matters enormously. Never make decisions about grand jury testimony or an immunity offer without experienced legal advice.

What Happens After an Indictment?

If a grand jury returns an indictment, the defendant is formally charged and the case moves forward. The defendant will be arraigned on the indictment — brought before a court, informed of the charges, and asked to enter a plea. The case then proceeds through pretrial stages, potential plea negotiations, and potentially trial.

Being indicted does not mean a person is guilty. The probable cause standard used by grand juries is far lower than proof beyond a reasonable doubt. An indicted defendant is presumed innocent and has the full set of constitutional rights that apply to any criminal defendant — including the Sixth Amendment right to counsel, the right to confront witnesses at trial, and the Fifth Amendment right not to testify against oneself.

What You Can Do

• If you receive a grand jury subpoena, do not ignore it. Contact a criminal defense attorney immediately — before responding to or appearing for the subpoena. The decision about how to respond, whether to invoke the Fifth Amendment, and what to say has major consequences.
• If you are a target or subject of a grand jury investigation, invoking your Fifth Amendment right not to testify may be the right approach, but this is a decision that requires legal advice specific to your situation.
• If you are indicted, ask the court for a public defender if you cannot afford a lawyer. The right to appointed counsel under Gideon v. Wainwright (1963) applies fully to indicted defendants.
• Attend all court dates after an indictment. Missing a court appearance can lead to a bench warrant and additional charges.

This is general legal information, not legal advice. Grand jury procedures differ significantly between the federal system and individual states. If you have received a grand jury subpoena or have been indicted, consult a licensed criminal defense attorney in your jurisdiction immediately — the stakes and the deadlines are serious.