Rule Six of the Federal Rules of Criminal Procedure describes grand juries. The government asks a court to order the creation of a grand jury. Typically, 16 jurors serve. As many as 23 jurors can serve.
While a grand jury is in session the following people may be present: attorneys for the government; the witness being questioned; interpreters if needed; or a court reporter or operator of a recording device. While the grand jury is deliberating or voting, no one other than the jurors and a necessary interpreter may be present.
Except for juror deliberations and voting, all proceedings must be recorded by a device or a court reporter. The validity of a prosecution isn’t affected by the unintentional failure to record. Unless the court orders otherwise, an attorney for the government retains control of any recording, reporters notes, and any transcripts.
Generally, grand jury proceedings are conducted in secrecy. The most relevant exception to the rule of secrecy is that information can be shared with states when there is a possibility that state law has been violated.
The subpoena power is governed by Rule 17 of the Federal Rules of Criminal Procedure. A subpoena must command the witness to attend and testify at the specified time and place. Subpoenas can also be used to order a witness to produce any books, documents, papers, other data, or objects the subpoena designates.
Citizens of and residents in the United States, whether in the United States or not, must comply with subpoenas.
A witness before a grand jury must either answer questions or exercise their Fifth Amendment right against self-incrimination. Testimony before grand juries is under oath.
Twelve jurors must vote in favor of an indictment.
The Department of Justice provides information about grand juries.