What Is a Grand Jury? How Indictments Work

Last updated: 21 October 2026. This guide explains grand juries in the US federal system and in US states, with a short comparison with England and Wales. It is general information, not legal advice.

Short answer: A grand jury is a group of 16 to 23 citizens who meet in private to decide whether prosecutors have enough evidence to charge someone with a serious crime. They do not decide guilt. If at least 12 federal grand jurors find probable cause, they return an indictment, the formal charge that sends the case towards trial.

Key takeaways

• The Fifth Amendment requires a grand jury indictment for serious federal crimes, which in practice means any federal felony punishable by more than one year in prison, unless the defendant waives it.
• A federal grand jury has 16 to 23 members, and at least 12 must agree before an indictment is returned. The test is probable cause, not proof beyond reasonable doubt.
• Proceedings are secret, the prosecutor runs them, there is no judge in the room, and the person under investigation has no right to appear or to present evidence.
• States are not bound by the federal rule. Roughly half require grand jury indictments for felonies, and England and Wales voted in 1933 to abolish grand juries.

What is a grand jury?

A grand jury is a body of ordinary citizens that screens criminal charges before trial. Its job is accusatory: it hears the prosecution’s evidence and decides whether there is probable cause to believe a crime was committed and that the person named committed it. If the answer is yes, it votes a “true bill” and an indictment issues. If not, it returns a “no bill” and that charge does not go forward on that evidence.

The requirement comes from the Fifth Amendment, which says 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”, with exceptions for military cases. Federal Rule of Criminal Procedure 7(a) puts that into practice: any offence punishable by death or by more than one year in prison must be prosecuted by indictment. A defendant can waive the right for non-capital felonies and be charged by a prosecutor’s written “information” instead, which often happens when a plea deal is agreed in advance.

A grand jury is different from the trial jury that most people picture. A trial jury, also called a petit or traverse jury, hears both sides in open court and decides guilt. Our explainer on traverse jury vs grand jury covers that comparison in more detail; this guide focuses on how indictments are actually obtained.

How does a grand jury indictment work?

Federal grand juries are governed mainly by Rule 6 of the Federal Rules of Criminal Procedure. The process usually runs like this:

1. The grand jury is empanelled. Rule 6(a) says a grand jury “must have 16 to 23 members”. According to the US federal courts, jurors usually serve for up to 18 months, or 24 if a judge extends the term, and they do not sit every day. In a smaller district they might meet one day every two weeks.
2. The prosecutor investigates. Grand juries have broad subpoena power. Prosecutors use it to compel witnesses to testify and companies or individuals to hand over documents, phone records and bank statements. Many cases are investigated for months before anyone is charged, as our guide to federal white-collar investigations explains.
3. Witnesses testify in private. The prosecutor questions each witness under oath. Grand jurors can usually ask questions too.
4. The prosecutor presents a draft indictment. The prosecutor explains the law and asks the grand jury to vote on specific charges.
5. The jurors deliberate alone. Under Rule 6(d), nobody other than the jurors may be present while they deliberate and vote, apart from an interpreter needed by a juror.
6. The vote. Rule 6(f) says a grand jury “may indict only if at least 12 jurors concur”. The indictment is then returned to a magistrate judge in open court.
7. Arrest or summons and arraignment. A judge can order an indictment sealed until the defendant is in custody. After that, the defendant is brought to court to enter a plea. Our guide to what happens at an arraignment covers the next stage.

Timing matters. For most federal crimes, the indictment must be returned within five years of the offence under 18 U.S.C. section 3282, although some offences have longer periods or none at all.

Who is in the grand jury room, and what rights do witnesses have?

While evidence is being heard, Rule 6(d) allows only the government’s lawyers, the witness being questioned, any interpreter and a court reporter. There is no judge and no defence lawyer. A witness who wants legal advice has to step outside to get it.

The Department of Justice’s Justice Manual sets out what prosecutors tell people under investigation. It uses two labels:

• a target is someone against whom there is “substantial evidence” linking them to a crime and whom the prosecutor sees as a “putative defendant”;
• a subject is someone whose conduct falls within the scope of the investigation.

Targets and subjects called to testify are told they may refuse to answer any question if a truthful answer would tend to incriminate them, and that the grand jury will give them “a reasonable opportunity to step outside the grand jury room to consult with counsel”. The manual also encourages prosecutors, in appropriate cases, to warn a target before seeking an indictment so that the person can ask to testify, but there is no legal right to do so.

Secrecy cuts one way. Rule 6(e) binds grand jurors, prosecutors, court reporters and interpreters. It does not bind witnesses, who are generally free to say what they were asked. A witness who refuses to testify without a valid privilege can be held in contempt and confined under 28 U.S.C. section 1826, but for no longer than the life of the grand jury and never more than 18 months.

How is a grand jury different from a preliminary hearing or a trial jury?

There are three main routes from arrest to trial in the US. The table compares them.

A federal case can also begin with a criminal complaint sworn before a magistrate, followed by an indictment within a set time. Our article on federal complaints and indictments explains that sequence.

Do all states use grand juries?

No. In Hurtado v. California (1884), the US Supreme Court held that the Fourteenth Amendment’s due process clause does not require states to prosecute felonies by grand jury indictment. California was allowed to charge by information after a magistrate’s examination, and that remains the position.

As a result, state practice varies widely. Columbia Law School professors Jeffrey Fagan and Bernard Harcourt noted in a 2014 fact sheet that about half of US states require a grand jury indictment for felony prosecutions, while in the others prosecutors generally file an information. Size, voting rules and term length all differ from the federal model, so check the rules of the state concerned.

Why do grand juries almost always indict?

Because the process is built for the prosecution. Several Supreme Court rulings explain why:

• No duty to present the defence case. In United States v. Williams (1992), the Court held 5 to 4 that a federal court cannot dismiss an indictment because prosecutors failed to show the grand jury “substantial exculpatory evidence”. Justice Scalia wrote that the grand jury “sits not to determine guilt or innocence”. DOJ policy does still tell prosecutors to disclose substantial evidence that directly negates guilt, but breaching that policy is not by itself a ground for dismissal.
• Hearsay is allowed. In Costello v. United States (1956), the Court upheld an indictment based only on hearsay, saying an indictment from “a legally constituted and unbiased grand jury”, if valid on its face, “is enough to call for trial of the charge on the merits”.
• Illegally obtained evidence can be used. In United States v. Calandra (1974), the Court held that a grand jury witness cannot refuse to answer questions on the ground that they rest on evidence from an unlawful search. Our guide to the motion to suppress explains how that evidence can still be challenged later, at trial.

The numbers reflect this. Federal statistics cited by Fagan and Harcourt show grand juries declined to indict in 11 of about 162,000 federal cases prosecuted in 2010. In 1985 Sol Wachtler, then chief judge of New York’s highest court, told the New York Daily News that a prosecutor could persuade a grand jury to “indict a ham sandwich”, a line still quoted by defence lawyers. Refusals do happen. In August 2025, CBS News reported that a federal grand jury in Washington, DC had declined to return a felony assault indictment against a man accused of throwing a sandwich at a federal officer; prosecutors then turned to a misdemeanour charge, which does not need a grand jury.

Does the UK have grand juries?

Not any more. Parliament passed the Administration of Justice (Miscellaneous Provisions) Act 1933, whose long title describes it as an Act “to abolish grand juries”. In England and Wales today, the police or the Crown Prosecution Service decide whether to charge, and the most serious cases go from the magistrates’ court to the Crown Court for trial by a jury of 12.

What should you do if you get a grand jury subpoena or target letter?

• Read it closely. A subpoena may ask you to testify, to produce documents, or both. It has a date and a named prosecutor.
• Find out your status. A lawyer can ask the prosecutor whether you are a witness, a subject or a target. That shapes everything else.
• Do not destroy or alter anything. Deleting emails or files after a subpoena arrives can lead to obstruction charges that are easier to prove than the original suspicion.
• Do not talk your way out of it. Informal conversations with agents can be used against you. See our guide on why you should not talk to the police without a lawyer.
• Get a criminal defence lawyer early. Counsel can negotiate the scope of a document request, prepare you to testify, advise on invoking the Fifth Amendment or seek immunity.

If an indictment follows, the charges will usually be graded by the maximum sentence. Our overview of federal felony classes explains what those grades mean.

Frequently asked questions

Does a grand jury decide if someone is guilty?

No. A grand jury only decides whether there is probable cause to charge. Guilt is decided later by a trial jury or judge, or by a guilty plea, and the prosecution must then prove the case beyond reasonable doubt.

How many grand jurors must agree to indict?

In federal court, at least 12 of the 16 to 23 grand jurors must vote for an indictment. State rules differ, so the number needed in a state grand jury depends on that state’s law.

Can I testify before the grand jury if I am the target?

There is no right to testify, but federal prosecutors are told to give reasonable requests favourable consideration. You would normally have to waive your privilege against self-incrimination on the record, which is risky without careful advice from a lawyer.

Are grand jury proceedings public?

No. They are held in private, and grand jurors and prosecutors must keep them secret under Rule 6(e). Witnesses in federal cases are not covered by that duty, and transcripts can be released only in limited situations approved by a court.

What is a sealed indictment?

It is an indictment that a judge orders to be kept secret, usually until the defendant is arrested or appears in court. Sealing helps stop a suspect from fleeing or destroying evidence once they learn they have been charged.

Can a grand jury refuse to indict?

Yes. If fewer than the required number vote for the charge, the grand jury returns a “no bill”. In federal cases this is rare, and prosecutors can sometimes present the case again to a different grand jury.

This article is general information about grand juries and indictments and is not legal advice. Procedures differ between federal and state courts and from state to state, so if you have received a subpoena or target letter, speak to a qualified criminal defence lawyer promptly.