Michigan law provides for several distinct types of grand jury. The citizen grand jury, drawn from the community under MCL 767.7, is summoned to hear evidence and determine whether probable cause exists to indict an accused person. The one-man grand jury, authorized by MCL 767.3 and MCL 767.4, operates through a circuit court judge who conducts an independent investigation with authority to subpoena witnesses and issue arrest warrants; the Michigan Supreme Court's decision in People v Peeler, 509 Mich 381 (2022), significantly cabined the one-man grand jury's authority, holding that a one-man grand jury cannot issue binding indictments in criminal proceedings and that an accused who is the subject of a one-man grand jury investigation is entitled to a preliminary examination before trial. The Court of Appeals's subsequent decision in People v Robinson, ___ Mich App ___ (2024), confirmed that an erroneous one-man grand jury indictment does not deprive the circuit court of subject-matter jurisdiction, providing a procedural pathway for affected defendants to challenge their prosecutions.

The Fifth Amendment privilege against self-incrimination is available to any grand jury witness who has reasonable cause to apprehend danger from a direct answer to the question asked. The privilege is not limited to questions that would themselves constitute an admission of guilt—it extends to any question whose truthful answer might provide a link in the chain of evidence needed to prosecute the witness. Counselman v Hitchcock, 142 US 547 (1892). In the grand jury context, a witness who has been granted use immunity under MCL 767.6 may be compelled to testify over a Fifth Amendment objection, because use immunity prevents the government from using the immunized testimony against the witness in a subsequent prosecution. Defense counsel must evaluate the scope of any immunity grant and ensure that its terms are sufficient to protect the witness before advising compliance with a compelled immunity order.

Grand jury witnesses are entitled to the appointment of counsel at public expense if they are financially unable to retain a lawyer. MCR 6.005(I)(1) provides that upon request, the chief judge in the circuit court in which the grand jury is convened will refer an indigent witness to the local indigent criminal defense system for appointment of counsel. Similarly, MCL 767A.4(g) requires that investigative subpoenas include a statement that witnesses may have legal counsel present at all times during questioning. The prosecutor assisting the grand jury is responsible for ensuring that witnesses are informed of the right to counsel by written notice accompanying the subpoena and by personal advice immediately before the examination.

The Michigan Supreme Court has held that the exclusionary rule does not apply to statutory violations of the investigative subpoena statutes, MCL 767A.1 et seq. People v Earls, 477 Mich 1119 (2007). This means that evidence gathered through a defective investigative subpoena may not be suppressed on statutory grounds alone—a significant limitation that underscores the importance of challenging the subpoena before complying rather than testifying and seeking suppression afterward. In People v Seals, 285 Mich App 1 (2009), the Court of Appeals held that a defendant who failed to object to an investigative subpoena under MCL 767A.6(1) could not later characterize his responsive testimony as involuntary. The lesson is clear: the time to challenge a subpoena is before testimony is given.

Grand jury proceedings require careful strategic analysis by defense counsel, including consideration of whether assertion of the Fifth Amendment is advisable, whether a motion to quash or limit the subpoena is appropriate, whether any immunity arrangement serves the client's interests, and whether preemptive contact with the prosecutor can affect the client's exposure. Attorney William Maze represents both witnesses and targets in grand jury proceedings in state court throughout Wayne County and in federal court in the Eastern District of Michigan, and is experienced in navigating all aspects of the grand jury process from first subpoena through return of indictment or declination of prosecution.