Information Establishing Probable Cause

(Current Modern Test)

ILLINOIS v. LANCE AND SUSAN GATES

462 U.S. 213 (1983)

 Justice REHNQUIST delivered the opinion of the Court.

  Respondents Lance and Susan Gates were indicted for violation of state drug laws after police officers, executing a search warrant, discovered marijuana and other contraband in their automobile and home. Prior to trial the Gates moved to suppress evidence seized during this search. The Illinois Supreme Court affirmed the decisions of lower state courts granting the motion. It held that the affidavit submitted in support of the State's application for a warrant to search the Gates' property was inadequate under this Court's decisions in Aguilar v. Texas and Spinelli v. United States. We granted certiorari to consider the application of the Fourth Amendment to a magistrate's issuance of a search warrant on the basis of a partially corroborated anonymous informant's tip.

A chronological statement of events usefully introduces the issues at stake. Bloomingdale, Ill., is a suburb of Chicago located in DuPage County. On May 3, 1978, the Bloomingdale Police Department received by mail an anonymous handwritten letter which read as follows:

The letter was referred by the Chief of Police of the Bloomingdale Police Department to Detective Mader, who decided to pursue the tip. Mader learned, from the office of the Illinois Secretary of State, that an Illinois driver's license had been issued to one Lance Gates, residing at a stated address in Bloomingdale. He contacted a confidential informant, whose examination of certain financial records revealed a more recent address for the Gates, and he also learned from a police officer assigned to O'Hare Airport that "L. Gates" had made a reservation on Eastern Airlines flight 245 to West Palm Beach, Fla., scheduled to depart from Chicago on May 5 at 4:15 p.m.

Mader then made arrangements with an agent of the Drug Enforcement Administration for surveillance of the May 5 Eastern Airlines flight. The agent later reported to Mader that Gates had boarded the flight, and that federal agents in Florida had observed him arrive in West Palm Beach and take a taxi to the nearby Holiday Inn. They also reported that Gates went to a room registered to one Susan Gates and that, at 7:00 a.m. the next morning, Gates and an unidentified woman left the motel in a Mercury bearing Illinois license plates and drove northbound on an interstate frequently used by travelers to the Chicago area. In addition, the DEA agent informed Mader that the license plate number on the Mercury registered to a Hornet station wagon owned by Gates. The agent also advised Mader that the driving time between West Palm Beach and Bloomingdale was approximately 22 to 24 hours.

Mader signed an affidavit setting forth the foregoing facts, and submitted it to a judge of the Circuit Court of DuPage County, together with a copy of the anonymous letter. The judge of that court thereupon issued a search warrant for the Gates' residence and for their automobile. The judge, in deciding to issue the warrant, could have determined that the modus operandi of the Gates had been substantially corroborated. As the anonymous letter predicted, Lance Gates had flown from Chicago to West Palm Beach late in the afternoon of May 5th, had checked into a hotel room registered in the name of his wife, and, at 7:00 a.m. the following morning, had headed north, accompanied by an unidentified woman, out of West Palm Beach on an interstate highway used by travelers from South Florida to Chicago in an automobile bearing a license plate issued to him.

At 5:15 a.m. on March 7th, only 36 hours after he had flown out of Chicago, Lance Gates, and his wife, returned to their home in Bloomingdale, driving the car in which they had left West Palm Beach some 22 hours earlier. The Bloomingdale police were awaiting them, searched the trunk of the Mercury, and uncovered approximately 350 pounds of marijuana. A search of the Gates' home revealed marijuana, weapons, and other contraband. The Illinois Circuit Court ordered suppression of all these items, on the ground that the affidavit submitted to the Circuit Judge failed to support the necessary determination of probable cause to believe that the Gates' automobile and home contained the contraband in question. This decision was affirmed in turn by the Illinois Appellate Court and by a divided vote of the Supreme Court of Illinois.

The Illinois Supreme Court concluded--and we are inclined to agree--that, standing alone, the anonymous letter sent to the Bloomingdale Police Department would not provide the basis for a magistrate's determination that there was probable cause to believe contraband would be found in the Gates' car and home. The letter provides virtually nothing from which one might conclude that its author is either honest or his information reliable; likewise, the letter gives absolutely no indication of the basis for the writer's predictions regarding the Gates' criminal activities. Something more was required, then, before a magistrate could conclude that there was probable cause to believe that contraband would be found in the Gates' home and car.

The Illinois Supreme Court also properly recognized that Detective Mader's affidavit might be capable of supplementing the anonymous letter with information sufficient to permit a determination of probable cause. In holding that the affidavit in fact did not contain sufficient additional information to sustain a determination of probable cause, the Illinois court applied a "two-pronged test," derived from our decision in Spinelli v. United States. The Illinois Supreme Court, like some others, apparently understood Spinelli as requiring that the anonymous letter satisfy each of two independent requirements before it could be relied on. J.A., at 5. According to this view, the letter, as supplemented by Mader's affidavit, first had to adequately reveal the "basis of knowledge" of the letter writer--the particular means by which he came by the information given in his report. Second, it had to provide facts sufficiently establishing either the "veracity" of the affiant's informant, or, alternatively, the "reliability" of the informant's report in this particular case.

The Illinois court, alluding to an elaborate set of legal rules that have developed among various lower courts to enforce the "two-pronged test," found that the test had not been satisfied. First, the "veracity" prong was not satisfied because, "there was simply no basis [for] ... conclud[ing] that the anonymous person [who wrote the letter to the Bloomingdale Police Department] was credible." The court indicated that corroboration by police of details contained in the letter might never satisfy the "veracity" prong, and in any event, could not do so if, as in the present case, only "innocent" details are corroborated. In addition, the letter gave no indication of the basis of its writer's knowledge of the Gates' activities. The Illinois court understood Spinelli as permitting the detail contained in a tip to be used to infer that the informant had a reliable basis for his statements, but it thought that the anonymous letter failed to provide sufficient detail to permit such an inference. Thus, it concluded that no showing of probable cause had been made.

We agree with the Illinois Supreme Court that an informant's "veracity," "reliability" and "basis of knowledge" are all highly relevant in determining the value of his report. We do not agree, however, that these elements should be understood as entirely separate and independent requirements to be rigidly exacted in every case,[footnote 5] which the opinion of the Supreme Court of Illinois would imply. Rather, as detailed below, they should be understood simply as closely intertwined issues that may usefully illuminate the commonsense, practical question whether there is "probable cause" to believe that contraband or evidence is located in a particular place.

This totality of the circumstances approach is far more consistent with our prior treatment of probable cause than is any rigid demand that specific "tests" be satisfied by every informant's tip. Perhaps the central teaching of our decisions bearing on the probable cause standard is that it is a "practical, nontechnical conception." "In dealing with probable cause, ... as the very name implies, we deal with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act." Our observation in regarding "particularized suspicion," is also applicable to the probable cause standard:

Moreover, the "two-pronged test" directs analysis into two largely independent channels--the informant's "veracity" or "reliability" and his "basis of knowledge." There are persuasive arguments against according these two elements such independent status. Instead, they are better understood as relevant considerations in the totality of circumstances analysis that traditionally has guided probable cause determinations: a deficiency in one may be compensated for, in determining the overall reliability of a tip, by a strong showing as to the other, or by some other indicia of reliability. Unlike a totality of circumstances analysis, which permits a balanced assessment of the relative weights of all the various indicia of reliability (and unreliability) attending an informant's tip, the "two-pronged test" has encouraged an excessively technical dissection of informants' tips, with undue attention being focused on isolated issues that cannot sensibly be divorced from the other facts presented to the magistrate.

We also have recognized that affidavits are normally drafted by nonlawyers in the midst and haste of a criminal investigation. Technical requirements of elaborate specificity once exacted under common law pleading have no proper place in this area. Likewise, search and arrest warrants long have been issued by persons who are neither lawyers nor judges, and who certainly do not remain abreast of each judicial refinement of the nature of "probable cause." The rigorous inquiry into the Spinelli prongs and the complex superstructure of evidentiary and analytical rules that some have seen implicit in our Spinelli decision, cannot be reconciled with the fact that many warrants are--quite properly, ibid.--issued on the basis of nontechnical, common-sense judgments of laymen applying a standard less demanding than those used in more formal legal proceedings. Likewise, given the informal, often hurried context in which it must be applied, the "built-in subtleties" of the "two-pronged test" are particularly unlikely to assist magistrates in determining probable cause.

Similarly, we have repeatedly said that after-the-fact scrutiny by courts of the sufficiency of an affidavit should not take the form of de novo review. A magistrate's determination of probable cause should be paid great deference by reviewing courts. A grudging or negative attitude by reviewing courts toward warrants, is inconsistent with the Fourth Amendment's strong preference for searches conducted pursuant to a warrant "courts should not invalidate ... warrants by interpreting affidavits in a hypertechnical, rather than a commonsense, manner."

Finally, the direction taken by decisions following Spinelli poorly serves the most basic function of any government: to provide for the security of the individual and of his property. The strictures that inevitably accompany the "two-pronged test" cannot avoid seriously impeding the task of law enforcement. If, as the Illinois Supreme Court apparently thought, that test must be rigorously applied in every case, anonymous tips seldom would be of greatly diminished value in police work. Ordinary citizens, like ordinary witnesses, generally do not provide extensive recitations of the basis of their everyday observations. Likewise, as the Illinois Supreme Court observed in this case, the veracity of persons supplying anonymous tips is by hypothesis largely unknown, and unknowable. As a result, anonymous tips seldom could survive a rigorous application of either of the Spinelli prongs. Yet, such tips, particularly when supplemented by independent police investigation, frequently contribute to the solution of otherwise "perfect crimes." While a conscientious assessment of the basis for crediting such tips is required by the Fourth Amendment, a standard that leaves virtually no place for anonymous citizen informants is not.

For all these reasons, we conclude that it is wiser to abandon the "two- pronged test" established by our decisions in Aguilar and Spinelli. In its place we reaffirm the totality of the circumstances analysis that traditionally has informed probable cause determinations. The task of the issuing magistrate is simply to make a practical, common-sense decision whether, given all the circumstances set forth in the affidavit before him, including the "veracity" and "basis of knowledge" of persons supplying hearsay information, there is a fair probability that contraband or evidence of a crime will be found in a particular place. And the duty of a reviewing court is simply to ensure that the magistrate had a "substantial basis for ... conclud[ing]" that probable cause existed. We are convinced that this flexible, easily applied standard will better achieve the accommodation of public and private interests that the Fourth Amendment requires than does the approach that has developed from Aguilar and Spinelli.

Our earlier cases illustrate the limits beyond which a magistrate may not venture in issuing a warrant. An officer's statement that "affiants have received reliable information from a credible person and believe" that heroin is stored in a home, is  inadequate. Aguilar v. Texas, 378 U.S. 108 (1964). [T]his is a mere conclusory statement that gives the magistrate virtually no basis at all for making a judgment regarding probable cause. Sufficient information must be presented to the magistrate to allow that official to determine probable cause; his action cannot be a mere ratification of the bare conclusions of others. In order to ensure that such an abdication of the magistrate's duty does not occur, courts must continue to conscientiously review the sufficiency of affidavits on which warrants are issued. But when we move beyond the "bare bones" affidavits present in cases such as  Aguilar, this area simply does not lend itself to a prescribed set of rules, like that which had developed from Spinelli. Instead, the flexible, common-sense standard articulated in [earlier cases] better serves the purposes of the Fourth Amendment's probable cause requirement.

The essential protection of the warrant requirement of the Fourth Amendment is in "requiring that [the usual inferences which reasonable men draw from evidence] be drawn by a neutral and detached magistrate instead of being judged by the officer engaged in the often competitive enterprise of ferreting out crime." Nothing in our opinion in any way lessens the authority of the magistrate to draw such reasonable inferences as he will from the material supplied to him by applicants for a warrant; indeed, he is freer than under the regime of Aguilar and Spinelli to draw such inferences, or to refuse to draw them if he is so minded.

The real gist of Justice BRENNAN's criticism seems to be a second argument, somewhat at odds with the first, that magistrates should be restricted in their authority to make probable cause determinations by the standards laid down in Aguilar and Spinelli, and that such findings "should not be authorized unless there is some assurance that the information on which they are based has been obtained in a reliable way by an honest or credible person." However, under our opinion magistrates remain perfectly free to exact such assurances as they deem necessary, as well as those required by this opinion, in making probable cause determinations. Justice BRENNAN would apparently prefer that magistrates be restricted in their findings of probable cause by the development of an elaborate body of case law dealing with the "veracity" prong of the Spinelli test, which in turn is broken down into two "spurs"--the informant's "credibility" and the "reliability" of his information, together with the "basis of knowledge" prong of the Spinelli test. That such a labyrinthine body of judicial refinement bears any relationship to familiar definitions of probable cause is hard to imagine.

The showing of probable cause in the present case was [compelling]. Even standing alone, the facts obtained through the independent investigation of Mader and the DEA at least suggested that the Gates were involved in drug trafficking. In addition to being a popular vacation site, Florida is well-known as a source of narcotics and other illegal drugs. Lance Gates flight to Palm Beach, his brief, overnight stay in a motel, and apparent immediate return north to Chicago in the family car, conveniently awaiting him in West Palm Beach, is as suggestive of a pre-arranged drug run, as it is of an ordinary vacation trip.

In addition, the magistrate could rely on the anonymous letter, which had been corroborated in major part by Mader's efforts. [Although the honesty and reliability of the anonymous informant in this case were unknown to the Bloomingdale police at the time the police department received the anonymous letter], it became far less significant after Mader's independent investigative work occurred. The corroboration of the letter's predictions that the Gates' car would be in Florida, that Lance Gates would fly to Florida in the next day or so, and that he would drive the car north toward Bloomingdale all indicated, albeit not with certainty, that the informant's other assertions also were true. "Because an informant is right about some things, he is more probably right about other facts," --including the claim regarding the Gates' illegal activity. This may well not be the type of "reliability" or "veracity" necessary to satisfy some views of the "veracity prong" of Spinelli, but we think it suffices for the practical, common-sense judgment called for in making a probable cause determination. It is enough, for purposes of assessing probable cause, that "corroboration through other sources of information reduced the chances of a reckless or prevaricating tale," thus providing "a substantial basis for crediting the hearsay."

  Finally, the anonymous letter contained a range of details relating not just to easily obtained facts and conditions existing at the time of the tip, but to future actions of third parties ordinarily not easily predicted. The letter writer's accurate information as to the travel plans of each of the Gates was of a character likely obtained only from the Gates themselves, or from someone familiar with their not entirely ordinary travel plans. If the informant had access to accurate information of this type a magistrate could properly conclude that it was not unlikely that he also had access to reliable information of the Gates' alleged illegal activities. Of course, the Gates travel plans might have been learned from a talkative neighbor or travel agent; under the "two-pronged test" developed from Spinelli, the character of the details in the anonymous letter might well not permit a sufficiently clear inference regarding the letter writer's "basis of knowledge." But, as discussed previously, supra, 2332, probable cause does not demand the certainty we associate with formal trials. It is enough that there was a fair probability that the writer of the anonymous letter had obtained his entire story either from the Gates or someone they trusted. And corroboration of major portions of the letter's predictions provides just this probability. It is apparent, therefore, that the judge issuing the warrant had a "substantial basis for ... conclud[ing]" that probable cause to search the Gates' home and car existed. The judgment of the Supreme Court of Illinois therefore must be reversed.

Justice WHITE, concurring in the judgment.

 I am inclined to believe that, when applied properly, the Aguilar-Spinelli rules play an appropriate role in probable cause determinations, and because the Court's holding may foretell an evisceration of the probable cause standard, I do not join the Court's holding.

The Court reasons that the "veracity" and "basis of knowledge" tests are not independent, and that a deficiency as to one can be compensated for by a strong showing as to the other. Thus, a finding of probable cause may be based on a tip from an informant "known for the unusual reliability of his predictions" or from "an unquestionably honest citizen," even if the report fails thoroughly to set forth the basis upon which the information was obtained. If this is so, then it must follow a fortiori that "the affidavit of an officer, known by the magistrate to be honest and experienced, stating that [contraband] is located in a certain building" must be acceptable. It would be "quixotic" if a similar statement from an honest informant, but not one from an honest officer, could furnish probable cause. But we have repeatedly held that the unsupported assertion or belief of an officer does not satisfy the probable cause requirement. Thus, this portion of today's holding can be read as implicitly rejecting the teachings of these prior holdings.

The Court may not intend so drastic a result. Indeed, the Court expressly reaffirms, the validity of cases  that have held that, no matter how reliable the affiant-officer may be, a warrant should not be issued unless the affidavit discloses supporting facts and circumstances. The Court limits these cases to situations involving affidavits containing only "bare conclusions" and holds that, if an affidavit contains anything more, it should be left to the issuing magistrate to decide, based solely on "practical[ity]" and "common-sense," whether there is a fair probability that contraband will be found in a particular place.

Thus, as I read the majority opinion, it appears that the question whether the probable cause standard is to be diluted is left to the common-sense judgments of issuing magistrates. I am reluctant to approve any standard that does not expressly require, as a prerequisite to issuance of a warrant, some showing of facts from which an inference may be drawn that the informant is credible and that his information was obtained in a reliable way. I believe, however, that with clarification of the rule of corroborating information, the lower courts are fully able to properly interpret Aguilar-Spinelli and avoid such unduly-rigid applications. Hence, I do not join the Court's opinion rejecting the Aguilar-Spinelli rules.

Justice BRENNAN, with whom Justice MARSHALL joins, dissenting.

Although I join Justice STEVENS dissenting opinion and agree with him that the warrant is invalid even under the Court's newly announced "totality of the circumstances" test, I write separately to dissent from the Court's unjustified and ill-advised rejection of the two-prong test for evaluating the validity of a warrant based on hearsay announced in Aguilar and refined in Spinelli.

The Court's current Fourth Amendment jurisprudence, as reflected by today's unfortunate decision, patently disregards Justice Jackson's admonition in Brinegar v. United States:

Properly understood,  Spinelli stands for the proposition that corroboration of certain details in a tip may be sufficient to satisfy the veracity, but not the basis of knowledge, prong of Aguilar. As noted, Spinelli also suggests that in some limited circumstances considerable detail in an informant's tip may be adequate to satisfy the basis of knowledge prong of Aguilar. 

In light of the important purposes served by Aguilar and Spinelli, I would not reject the standards they establish. If anything, I simply would make more clear that Spinelli, properly understood, does not depart in any fundamental way from the test established by Aguilar. For reasons I shall next state, I do not find persuasive the Court's justifications for rejecting the test established by Aguilar and refined by Spinelli.

In rejecting the Aguilar-Spinelli standards, the Court suggests that a "totality of the circumstances approach is far more consistent with our prior treatment of probable cause than is any rigid demand that specific tests be satisfied by every informant's tip." In support of this proposition the Court relies on several cases that purportedly reflect this approach and on the "practical, nontechnical" nature of probable cause.

[O]ne can concede that probable cause is a "practical, nontechnical" concept without betraying the values that Aguilar and Spinelli reflect. As noted, Aguilar and Spinelli require the police to provide magistrates with certain crucial information. They also provide structure for magistrates probable cause inquiries. In so doing, Aguilar and Spinelli preserve the role of magistrates as independent arbiters of probable cause, insure greater accuracy in probable cause determinations, and advance the substantive value of precluding findings of probable cause, and attendant intrusions, based on anything less than information from an honest or credible person who has acquired his information in a reliable way. Neither the standards nor their effects are inconsistent with a "practical, nontechnical" conception of probable cause. Once a magistrate has determined that he has information before him that he can reasonably say has been obtained in a reliable way by a credible person, he has ample room to use his common sense and to apply a practical, nontechnical conception of probable cause.

It also should be emphasized that cases such as Nathanson v. United States, and Giordenello v. United States directly contradict the Court's suggestion that a strong showing on one prong of the Aguilar test should compensate for a deficient showing on the other. If the conclusory allegations of a presumptively reliable police officer are insufficient to establish probable cause, there is no conceivable reason why the conclusory allegations of an anonymous informant should not be insufficient as well. Moreover, contrary to the Court's implicit suggestion, Aguilar and Spinelli do not stand as an insuperable barrier to the use of even anonymous informants' tips to establish probable cause. It is no justification for rejecting them outright that some courts may have employed an overly technical version of the Aguilar-Spinelli standards.

The Court also insists that the Aguilar-Spinelli standards must be abandoned because they are inconsistent with the fact that non-lawyers frequently serve as magistrates. To the contrary, the standards help to structure probable cause inquiries and, properly interpreted, may actually help a non-lawyer magistrate in making a probable cause determination. Moreover, the Aguilar and Spinelli tests are not inconsistent with deference to magistrates' determinations of probable cause. Aguilar expressly acknowledged that reviewing courts "will pay substantial deference to judicial determinations of probable cause...." In Spinelli, the Court noted that it was not retreating from the proposition that magistrates' determinations of probable cause "should be paid great deference by reviewing courts...." * * *

By replacing Aguilar and Spinelli with a test that provides no assurance that magistrates, rather than the police, or informants, will make determinations of probable cause; imposes no structure on magistrates' probable cause inquiries; and invites the possibility that intrusions may be justified on less than reliable information from an honest or credible person, today's decision threatens to obliterate one of the most fundamental distinctions between our form of government, where officers are under the law, and the police-state where they are the law.

Justice STEVENS, with whom Justice BRENNAN joins, dissenting.

The fact that Lance and Sue Gates made a 22-hour nonstop drive from West Palm Beach, Florida, to Bloomingdale, Illinois, only a few hours after Lance had flown to Florida provided persuasive evidence that they were engaged in illicit activity. That fact, however, was not known to the magistrate when he issued the warrant to search their home.

The discrepancy between the informant's predictions and the facts known to Detective Mader is significant for three reasons. First, it cast doubt on the informant's hypothesis that the Gates already had "over $100,000 worth of drugs in their basement," The informant had predicted an itinerary that always kept one spouse in Bloomingdale, suggesting that the Gates did not want to leave their home unguarded because something valuable was hidden within. That inference obviously could not be drawn when it was known that the pair was actually together over a thousand miles from home.

Second, the discrepancy made the Gates' conduct seem substantially less unusual than the informant had predicted it would be. It would have been odd if, as predicted, Sue had driven down to Florida on Wednesday, left the car, and flown right back to Illinois. But the mere facts that Sue was in West Palm Beach with the car, that she was joined by her husband at the Holiday Inn on Friday, and that the couple drove north together the next morning are neither unusual nor probative of criminal activity.

Third, the fact that the anonymous letter contained a material mistake undermines the reasonableness of relying on it as a basis for making a forcible entry into a private home.

Of course, the activities in this case did not stop when the magistrate issued the warrant. The Gates drove all night to Bloomingdale, the officers searched the car and found 400 pounds of marijuana, and then they searched the house. However, none of these subsequent events may be considered in evaluating the warrant, and the search of the house was legal only if the warrant was valid. I cannot accept the Court's casual conclusion that, before the Gates arrived in Bloomingdale, there was probable cause to justify a valid entry and search of a private home. No one knows who the informant in this case was, or what motivated him or her to write the note. Given that the note's predictions were faulty in one significant respect, and were corroborated by nothing except ordinary innocent activity, I must surmise that the Court's evaluation of the warrant's validity has been colored by subsequent events.

In apologizing for its belated realization that we should not have ordered reargument in this case, the Court today shows high regard for the appropriate relationship of this Court to state courts. When the Court discusses the merits, however, it attaches no weight to the conclusions of the Circuit Judge of DuPage County, Illinois, of the three judges of the Second District of the Illinois Appellate Court, or of the five justices of the Illinois Supreme Court, all of whom concluded that the warrant was not based on probable cause. In a fact-bound inquiry of this sort, the judgment of three levels of state courts, all of whom are better able to evaluate the probable reliability of anonymous informants in Bloomingdale, Illinois, than we are, should be entitled to at least a presumption of accuracy.