What initiates any criminal action in the United States?

In the context of criminal action in the United States, the initiation of proceedings typically begins with a complaint. A complaint is a formal legal document that outlines the allegations against a person, stating what laws have been violated and providing specific details about the offense. It is crucial in the criminal justice process as it serves as the foundation for the case, setting in motion the legal proceedings.

An investigation, while essential for gathering evidence and determining whether a crime has been committed, does not formally initiate criminal action. Similarly, a warrant, which is issued by a judge, allows law enforcement to take specific actions, such as making an arrest or conducting a search, but it arises after an investigation and is contingent upon sufficient cause. An indictment occurs after a complaint has been filed and is typically used in felony cases when a grand jury formally charges someone with a crime.

Understanding that a complaint is the document that officially begins the prosecution of a criminal case helps clarify its significance in the legal process.