What does probable cause mean in a grand jury investigation?

In a grand jury investigation, probable cause refers to the existence of reasonable grounds to believe that a person has committed a crime. It serves as the legal standard the grand jury must evaluate to determine if a formal indictment is warranted.12

Essentially, the grand jury acts as a check to ensure that a charge is well-founded before an accused person is forced to stand trial. During the proceedings, jurors review evidence presented by prosecutors—such as witness testimony and subpoenaed records—to decide if there is sufficient basis to proceed. If the required number of jurors finds that probable cause exists, they issue an indictment, moving the case toward a trial where a petit jury will later determine guilt beyond a reasonable doubt. If they do not find such grounds, no indictment is issued.132