Definition
A grand jury is a group of citizens convened to examine evidence and decide whether there is probable cause to formally charge a person with a crime. If the grand jury finds probable cause, it returns an indictment that begins the formal prosecution. Unlike a trial jury, a grand jury does not decide guilt or innocence—it only determines whether charges should be brought.
Legal Meaning
The grand jury is a centuries-old institution rooted in English common law and enshrined in American law by the Fifth Amendment, which 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." Its function is to serve as a buffer between the citizen and the prosecutor: before the state can subject someone to a felony trial, a body of ordinary citizens must agree that the evidence justifies charges. This screening role distinguishes the grand jury from the petit (trial) jury, which determines guilt.
A grand jury operates very differently from a trial. It meets in secret, hears evidence presented by the prosecutor, and may subpoena witnesses and documents through its broad investigative powers. The target of the investigation typically has no right to be present, to cross-examine witnesses, or to present a defense, and defense attorneys are usually barred from the grand jury room. Because only the prosecution's side is heard and the standard is merely probable cause rather than proof beyond a reasonable doubt, grand juries return indictments in the vast majority of cases brought before them.
Practice varies sharply between the federal system and the states. The Fifth Amendment's grand jury requirement applies to serious federal offenses, but the Supreme Court has held that this particular guarantee is not binding on the states. As a result, some states require grand jury indictment for felonies, while others permit prosecutors to charge by filing an "information" following a preliminary hearing where a judge finds probable cause. Many states use both methods. Understanding which process applies is important in any criminal defense matter.
Key Points
- A grand jury decides whether there is probable cause to charge—not guilt or innocence
- If it finds probable cause, it returns an indictment that starts the formal case
- The Fifth Amendment requires grand jury indictment for serious federal crimes
- This requirement does not automatically bind the states, so practice varies widely
- Some states use grand juries; others allow charging by "information" after a hearing
- Grand juries meet in secret and hear only the prosecutor's evidence
- The target usually cannot attend, and defense lawyers are barred from the room
- Grand juries have broad power to subpoena witnesses and documents
Real-World Example
Federal prosecutors investigating a complex fraud scheme present documents and witness testimony to a grand jury over several weeks. The grand jury uses its subpoena power to compel bank records and the testimony of employees. After reviewing the evidence, the grand jurors vote on whether probable cause exists to believe the suspect committed wire fraud. Because at least the required number of jurors agree, the grand jury returns an indictment—a "true bill"—formally charging the suspect, who is then arrested and brought to court for arraignment. Had the grand jury declined to charge, it would have returned a "no bill," and the case would not have proceeded on those charges at that time.
Grand Jury vs. Trial Jury
| Feature | Grand Jury | Trial (Petit) Jury |
|---|---|---|
| Purpose | Decide whether to charge | Decide guilt or innocence |
| Standard | Probable cause | Beyond a reasonable doubt |
| Size | Larger (often 16–23) | Smaller (commonly 6–12) |
| Setting | Secret; prosecutor only | Open court; both sides present |
| Defendant present? | Usually not | Yes |
| Outcome | Indictment (true bill) or no bill | Verdict of guilty or not guilty |
Powers and Limits of the Grand Jury
The grand jury has substantial investigative authority but operates within important limits:
- Subpoena power: It can compel witnesses to testify and require production of documents and records.
- Probable cause standard: It needs only probable cause to indict, far less than the trial standard.
- Witness rights: Witnesses keep their Fifth Amendment privilege against self-incrimination and may consult counsel outside the room.
- Secrecy: Proceedings are confidential to protect witnesses, the uncharged, and the integrity of the investigation.
- No determination of guilt: An indictment is only an accusation; guilt must still be proven at trial.
Because an indictment is not a finding of guilt, a person charged by a grand jury retains all trial rights, including the presumption of innocence and the protection against double jeopardy.
Related Terms
Subpoenaed by a Grand Jury?
A criminal defense lawyer can protect your rights before you testify
Find Criminal Defense HelpWhen You Need a Lawyer
Anyone involved in a grand jury proceeding—as a target, subject, or witness—should consult a criminal defense attorney. A lawyer can:
- Explain whether you are a witness, a subject, or a target of the investigation
- Advise you on your Fifth Amendment rights before you testify
- Help you respond properly to a grand jury subpoena for testimony or documents
- Negotiate with prosecutors, including over immunity, where appropriate
- Prepare a defense in case the grand jury returns an indictment
If an indictment is returned, the case moves toward arraignment and beyond. Learn how the broader process works in our criminal defense practice area.
Frequently Asked Questions
What does a grand jury do?
A grand jury reviews evidence presented by a prosecutor and decides whether there is probable cause to formally charge someone with a crime. If the grand jury finds probable cause, it returns an indictment, which begins the formal criminal case. The grand jury does not decide guilt or innocence; that is the role of the trial jury at trial.
What is the difference between a grand jury and a trial jury?
A grand jury decides whether there is enough evidence to charge someone, while a trial jury (petit jury) decides whether a charged defendant is guilty. Grand juries are larger, meet in secret, hear only the prosecution's evidence, and apply the probable cause standard. Trial juries are smaller, hear both sides in an open courtroom, and must find guilt beyond a reasonable doubt.
Is a grand jury required to charge someone with a crime?
It depends on the jurisdiction. The Fifth Amendment requires a grand jury indictment for serious federal crimes, but the Supreme Court has held this requirement does not automatically apply to the states. Many states use grand juries, while others allow prosecutors to charge by filing an "information" after a preliminary hearing. The practice varies widely from state to state.
Are grand jury proceedings secret?
Yes. Grand jury proceedings are conducted in secret. The target of the investigation usually is not present, has no right to attend, and often has no defense attorney inside the room. Secrecy is meant to encourage witnesses to testify freely, protect the reputation of people who are investigated but not charged, and prevent suspects from fleeing or tampering with evidence.
Can you have a lawyer with you before a grand jury?
A witness testifying before a grand jury generally cannot have their attorney inside the grand jury room, although the witness can typically consult with counsel outside. Witnesses retain important rights, including the Fifth Amendment privilege against self-incrimination, and many witnesses are advised by a lawyer before and between sessions. The exact rules vary by jurisdiction.