Brief Fact Summary. An undercover narcotics officer engaged the respondent, Mandujano (the “respondent”), in a negotiation to purchase an ounce of heroin for six hundred fifty dollars. The transaction was never completed. The respondent was then called before the grand jury, where he testified to his knowledge regarding the heroin traffic in San Antonio. He was not given Miranda warnings before testifying.
Synopsis of Rule of Law. A witness called to testify before a grand jury need not be given Miranda warnings, and as a result statements made during a witness’s testimony need not be suppressed during any subsequent prosecution for perjury.
Probing questions to all types of witnesses is the stuff that grand jury investigations are made of; the grand jury's mission is, after all, to determine whether to make a presentment or return an indictment.View Full Point of Law
Issue. Whether Miranda warnings must be given to a grand jury witness called to testify about criminal matters in which he may have been involved and whether, absent those warnings, false statements made to the grand jury must be suppressed in a subsequent prosecution for perjury?
Held. The plurality opinion holds that Miranda warnings need not be given to a person called to testify before the grand jury and that false statements given during that testimony need not be suppressed in a subsequent prosecution for perjury.
Concurrence. Justice William Brennan (“J. Brennan”) writes separately to reiterate his previously stated view that the Fifth Amendment of the Constitution must be protected against erosion, and that the prosecutor in a grand jury proceeding does bear some burden to make the witness aware of his privilege against self incrimination guaranteed by the Fifth Amendment, and should be prohibited from calling a witness that he has reason to believe, by an objective standard, has committed a crime about which the government will seek to question him.
Justice Potter Stewart (“J. Stewart”) writes separately in concurrence to suggest reversal of the Court of Appeals without reaching anything except the narrow issue of whether the grand jury testimony could be used in a prosecution for perjury. He would not reach the issue in regard to other prosecutions arguably tainted by prosecutorial misconduct.
Discussion. In accordance with the Court of Appeals’ own precedent, the Supreme Court reversed the Court of Appeals in this matter, holding that the constitutional guarantee “related to the past, and does not endow the person who testifies with a license to commit perjury.” The witness called before the grand jury may assert the Fifth Amendment privilege against self-incrimination, but may not assert that privilege in order to perjure himself. Moreover, the custodial interrogation of a witness at the hands of the police and the questioning of a witness at a grand jury proceeding are not equivalent, obviating the need for Miranda warnings during the latter situation.