428 U.S. 338 (1976)
In December 1970, federal agents obtained a search warrant for respondent John Calandra's place of business, the Royal Machine & Tool Co. in Cleveland, Ohio, authorizing the seizure of bookmaking records and wagering paraphernalia in connection with an investigation of suspected illegal gambling operations.1
The supporting affidavit included information from confidential informants, physical surveillance by FBI agents, and court-authorized electronic surveillance.2 On December 15, 1970, the agents conducted a four-hour search of the two-story building, spending more than three hours in Calandra's office on the second floor.3 Although the search yielded no gambling paraphernalia, an agent discovered a card among promissory notes showing periodic payments by Dr. Walter Loveland to Calandra.4
Believing this to be a loansharking record related to an ongoing investigation of extortionate credit transactions under 18 U.S.C. §§ 892, 893, and 894, the agent seized the card along with company books and records, stock certificates, and address books.5 On March 1, 1971, a special grand jury was convened in the Northern District of Ohio to investigate possible loansharking activities.6
The grand jury issued a subpoena to Calandra to question him based on the seized evidence.7 Calandra appeared on August 17, 1971, but refused to testify, claiming his Fifth Amendment privilege against self-incrimination.8 The Government applied for transactional immunity under 18 U.S.C. § 2514, prompting Calandra to seek a postponement to prepare a suppression motion.9 Calandra moved under Federal Rule of Criminal Procedure 41(e) for suppression and return of the seized evidence, contending the affidavit was insufficient and the search exceeded the warrant's scope.10
Following a hearing on August 27, 1971, at which Calandra stipulated he would refuse to answer questions based on the materials, the District Court on October 1, 1971, ordered the evidence suppressed and returned and ruled that Calandra need not answer any grand jury questions based on the suppressed evidence.11 The Court of Appeals for the Sixth Circuit affirmed.12 The Supreme Court granted certiorari.13
Whether a witness summoned to appear and testify before a grand jury may refuse to answer questions on the ground that they are based on evidence obtained from an unlawful search and seizure?14
The exclusionary rule operates as a judicially created remedy.15 Its purpose is to deter future unlawful police conduct rather than to redress individual injuries from past violations.16 Grand jury proceedings have historically been free from the technical rules of evidence that govern trials.17 This allows the body to investigate broadly and return indictments based on evidence that might be inadmissible at trial.18 Extending the exclusionary rule to permit a grand jury witness to refuse testimony derived from an unlawful search would substantially impair the grand jury's efficiency and effectiveness.19 It would provide no more than a marginal increase in deterrence of Fourth Amendment violations.20
No. The Court weighed the damage to the grand jury's historic functions against any incremental deterrent benefit. It found the former predominant when applied to the facts of this investigation.21
The December 15, 1970 search of the Royal Machine & Tool Co. produced the loansharking record that formed the basis for the grand jury's subpoena to Calandra after the body was convened on March 1, 1971.22 Calandra appeared in August 1971, received an offer of immunity, and then moved under Rule 41(e) to suppress the evidence before answering any questions.23
Permitting the witness to invoke the exclusionary rule would have required the grand jury to suspend its inquiry for a suppression hearing of the sort conducted by the District Court on August 27, 1971, and resolved on October 1, 1971.24 Such interruptions convert the grand jury's ex parte investigation into protracted litigation only tangentially related to its accusatorial mission.25
The seized evidence would remain inadmissible in any later criminal prosecution of Calandra.26 Therefore, the additional deterrence from barring its derivative use before the grand jury is speculative at best.27 It does not justify the impairment of the grand jury's ability to investigate extortionate credit transactions under 18 U.S.C. §§ 892-894.28
Related opinions on this issue
Joined by Mr. Justice Douglas And Mr. Justice Marshall
Justice Brennan dissented on the ground that the exclusionary rule is an essential component of the Fourth Amendment itself.31 It is necessary to preserve judicial integrity and prevent courts from becoming partners in official lawlessness.32 He maintained that Silverthorne Lumber Co. v. United States directly controls this case.33
That decision barred a grand jury from compelling production of documents derived from an earlier unlawful seizure.34 Brennan stressed that forcing Calandra to answer questions founded on the illegal search thwarts the Amendment's privacy protection.35 It also entangles the judiciary in the very conduct the Constitution forbids.36
This is contrary to the principles set forth in Weeks v. United States and Mapp v. Ohio.37 He viewed the majority's deterrence-only analysis as a retreat that risks eventual abandonment of the rule even at trial.38