Which legal document formally charges a person with a crime?

The correct choice, which refers to the legal document that formally charges a person with a crime, is the indictment. An indictment is a written accusation initiated by a grand jury that asserts there is enough evidence to charge an individual with a particular crime. This process typically occurs in more serious criminal cases, particularly felonies. The grand jury, composed of citizens, reviews evidence presented by the prosecutor and decides whether sufficient grounds exist to bring formal charges against the accused, thereby initiating criminal proceedings.

Understanding the function of an indictment is crucial in the criminal justice system, as it reflects the decision-making process of a grand jury and serves as an essential safeguard in ensuring that individuals are not subjected to prosecution without adequate evidence.

Other options, while relevant in different legal contexts, do not serve the purpose of formally charging someone with a crime. An affidavit involves a sworn written statement, a complaint typically refers to an initial document filed in civil litigation or a summary of a criminal charge, and a contract is a legally binding agreement between parties but has no role in criminal proceedings.