How do grand juries decide to return an indictment—burden of proof and voting thresholds?

1. How grand juries decide: probable cause, not guilt

Federal grand juries decide whether there is probable cause to believe a crime occurred and that the accused committed it; they do not determine guilt beyond a reasonable doubt — that is the role of a trial jury ^{[2] [3]}. The standard they apply is substantially lower than the criminal-conviction standard: prosecutors often present evidence to grand jurors and the jurors vote on whether the evidence meets probable cause ^{[1] [2]}.

2. The numeric threshold: 12 votes in federal practice

Rule 6 of the Federal Rules of Criminal Procedure, reflected in legal summaries and reporting, requires at least 12 grand jurors to concur to return a federal indictment (a “true bill”) when a grand jury is composed according to federal norms (typically 16–23 members) ^{[2] [3] [7]}. Major news outlets and the Associated Press repeatedly state that “twelve votes” are needed in federal grand juries ^{[1] [8]}.

3. Process mechanics: secrecy, forepersons, and returning the indictment

Grand jury proceedings are secret; prosecutors present evidence and witnesses and the grand jury votes in private. When an indictment is “returned,” it is typically signed by the grand jury foreperson and filed in court as the grand jury’s action ^{[4] [2]}. Reporting on the Comey matter indicates the foreperson and one other juror signed or reviewed a revised draft in court after the grand jury had earlier voted on a different proposed draft ^{[4] [6]}.

4. The Comey twist: prosecutors say full jury didn’t see the final draft

In the Comey hearing, prosecutors acknowledged that after the grand jury voted on a three-count proposal and rejected one count, they presented an altered two-count version to the court that, according to prosecutors, only the foreperson and another juror had seen before it was filed — meaning the full grand jury did not review or vote on that final text ^{[4] [5] [9]}. The Justice Department contends the counts in the filed indictment are identical in substance and reflect the counts the grand jury approved, differing only in numbering and paragraph structure ^[6].

5. Legal and practical stakes: why procedure matters

Defense counsel in the Comey proceedings argue the indictment should be dismissed because the grand jury never voted on the exact instrument filed, invoking the Fifth Amendment protection that felonies in federal court require an indictment by a grand jury ^{[10] [9]}. The government argues that where an indictment merely mirrors the counts the grand jury voted to return, wholesale dismissal may not be required — and past precedent can allow courts some latitude on irregularities ^{[6] [4] [3]}. Available sources do not provide a final judicial ruling resolving that legal dispute in this case ^{[6] [4]}.

6. Competing narratives and hidden incentives

Prosecutors framed their handling as a ministerial revision reflecting the jury’s vote; defense lawyers frame the same facts as a constitutional defect that could topple the prosecution ^{[4] [9]}. Observers note grand jury secrecy and the prosecutor’s control over presentation can create perceptions of prosecutorial advantage or overreach; reporting emphasizes both the rarity and significance of admitting the full grand jury didn’t see the filed indictment ^{[4] [9]}.

7. Bottom line for readers

Procedurally, federal indictments require probable cause and at least 12 grand juror votes ^{[2] [3]}. The Comey reporting shows an unusual mismatch between what the full grand jury voted on and the document filed in court; courts will decide whether that mismatch is fatal, and reporting so far documents the dispute rather than a conclusive legal resolution ^{[4] [9]}. Available sources do not mention any final appellate outcome or definitive judicial dismissal yet ^{[6] [9]}.