Final answer:
A petit jury is responsible for determining guilt at the trial level. Grand juries only decide if there's enough evidence for a trial, and judges oversee proceedings and ensure fairness. Prosecutors present the case against the defendant but do not determine guilt.
Step-by-step explanation:
A petit jury determines guilt at the trial level. A petit jury is a standard jury that most people think of when imagining a trial; they are responsible for listening to the evidence, deliberating, and then determining whether the defendant is guilty or not guilty of the charges against them. During a criminal trial, it is the prosecution's job to prove the defendant's guilt beyond a reasonable doubt, and the defense's role to maintain the client's innocence or rebut the prosecution's evidence. The process of jury deliberation is crucial to uphold the justice system, ensuring that individuals are judged by an impartial group of their peers rather than solely by the legal system's elite.
Grand juries serve a different purpose. They do not determine guilt or innocence; instead, they decide whether there is enough evidence to charge someone with a crime and proceed to a criminal trial. Trials can only commence after an indictment has been issued by a grand jury in the federal system, as underlined by the Fifth Amendment.
Judges oversee the proceedings, ensure fairness, and rule on points of law, but they do not usually decide on guilt unless the defendant chooses a bench trial (a trial without a jury). The prosecutor is responsible for presenting the case against the defendant in an attempt to demonstrate that they are guilty of the charges brought against them.