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Law 101: Legal Guide for the Forensic Expert

Grand Juries

Jurisdictions most frequently use grand juries to determine if there is probable cause to charge an individual with a criminal offense. 

Grand juries are created by statute to investigate whether a possible criminal violation has occurred. When the grand jury believes there is probable cause that a criminal violation has occurred and a corporation or individual is culpable, the grand jury will return an indictment (referred to as a "true bill") against the culpable party. 

  • The number of individuals comprising the grand jury is determined by statute and may range from seven to 30. The period of time a grand jury is empanelled is also determined by statute.  

  • The prosecuting authority directs the proceedings of the grand jury. During the process of questioning witnesses, grand jurors may ask questions as part of their broad investigative authority.  

  • The potential defendant may be absent during grand jury proceedings, depending on the jurisdiction. Whether the potential defendant and his counsel are required to be present during grand jury proceedings is dependent on jurisdictional rules or procedures.  

  • A grand jury is vested with the same authority as a judge to issue an arrest warrant. A grand jury uses the same standard as a judge regarding the quality or sufficiency of evidence.  

  • Similarly, in order to decide if there is a reasonable belief that a person committed a particular crime, a grand jury may consider sworn testimony delivered in an affidavit in addition to other evidence.

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