The fourth amendment guarantees in part that "The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures shall not be violated, and no warrants shall issue but upon probable cause.…" The determination of probable cause necessarily turns on specific facts and often requires the courts and the police to make most difficult decisions. The need for probable cause in American criminal procedure arises in three instances: probable cause to arrest or detain, probable cause to search, and probable cause to prosecute. The first two derive constitutional status directly from the Fourth Amendment and govern the conduct of the police. An inquiry by a judge or grand jury into probable cause for prosecution is not constitutionally required in state cases; however, this check on the exercise of prosecutorial discretion is prescribed by statute or state constitutional mandate in most states and is constitutionally required by the Fifth Amendment in federal cases.
As to arrest and search, the language of the Fourth Amendment does not distinguish between searches and seizures of objects, and arrests—"seizures" of the person. While one might assume that the term would have equivalent meanings in both the search and arrest contexts, the differences between arrests of suspects and searches for evidence or contraband require the probable cause standard to be applied to different types of data for the two procedures. Probable cause for a search does not automatically support an arrest, nor does a valid arrest warrant necessarily support a search.
Probable cause in the arrest context was defined by the United States Supreme Court in Beck v. Ohio (1964) as turning on "whether at that moment [of arrest] the facts and circumstances within [the officers'] knowledge and of which they [have] reasonably trustworthy information [are] sufficient to warrant a prudent man in believing that the [suspect] had committed or was committing an offense. There are two potential sources of information—personal knowledge and "trustworthy" secondary data. The Supreme Court has clearly established that secondary data—information not within the officer's personal knowledge—can supply sufficient grounds for an arrest. Thus, the police may rely on reports from other cities or states to support valid arrests, as in Whitely v. Warden (1971). Credible information supplied by an informant may also be used.
The officer's specific knowledge derived from direct contact with the arrestee is usually the primary support for a finding of probable cause. It is clear such information must be specific. Mere knowledge that, for example, a suspect has been convicted in the past coupled with an unidentified informant ' stip alleging current criminal activity has been held to be insufficient.
Even specific evidence linking an individual to a crime will not justify an arrest if the evidence has been discovered unconstitutionally. An arrest cannot be justified by evidence seized pursuant to the arrest; as the Court said in Sibron v. New York (1968): "An incident search may not precede an arrest and serve as part of its justification."
Evidence discovered in an on-street investigative encounter that has not yet reached the level of an arrest may be properly used to create probable cause. For example, if as a result of a stop-and-frisk encounter on the street, authorized by terry v. ohio (1968), an officer feels a weapon, he has probable cause to arrest for carrying a concealed weapon. Similarly, if in the course of a temporary detention the suspect fails adequately to account for his suspicious actions or if he affirmatively discloses incriminating evidence, probable cause to arrest may be established. The same is true if the suspect runs away. While flight alone does not create probable cause to arrest, it is a significant factor to be considered in the overall assessment.
By contrast, however, as the Court held in Brown v. Texas (1979), the mere failure of a suspect to identify himself, without more, does not supply probable cause. Nor may a valid arrest rely on an individual's failure to protect his innocence when found with suspects for whom probable cause exists, as in United States v. Di Re (1948).
Di Re also stands for the proposition that mere presence of an individual in the company of others who are properly suspected of criminal activity does not constitute probable cause. Subsequent cases, however, have made clear that there are limits to this principle. The difficulties here have largely come with possessory offenses. On the one hand, the Court in Johnson v. United States (1947) held that a tip that opium was being smoked coupled with the smell of opium outside a hotel room did not give rise to probable cause to arrest everyone in the room. Although there was probable cause to believe a crime was being committed, there was insufficient information to determine who was committing it. Yet in ker v. california (1963) the Court upheld the arrest of a married couple found in their kitchen with a brick of marijuana, even though the tip leading them there had linked only the husband to the contraband. The Court reasoned that the combination of the wife's presence in a small kitchen with obvious contraband, coupled with information that the husband had been using the apartment as a base for his drug activities, gave sufficient grounds for a reasonable belief that they were both in possession of marijuana.
This requirement of linking probable cause specifically to the arrestee was again mentioned by the Court in ybarra v. illinois (1979). There the police procured a valid warrant to search a tavern believed to be the center of drug activity. In executing the warrant, the police searched about a dozen of the tavern's patrons, including Ybarra. While the case thus actually dealt with the legitimacy of the search rather than an arrest, the Court stated: "[W]here the standard is probable cause, a search or seizure of a person must be supported by probable cause particularized with respect to that person. This requirement cannot be undercut or avoided by simply pointing to the fact that coincidentally there exists probable cause to search or seize another or to search the premises where the person may happen to be." (Emphasis added.) Ybarra thus reinforces the requirement that probable cause be particularized to the person arrested; mere presence at a place connected with criminal activity, or in the company of suspected criminals, without more, is inadequate.
Finally, the Court held in Gerstein v. Pugh (1975) that whenever a suspect has been arrested without a warrant and with no prior indictment, he is entitled to a quick judicial check on the police conclusion that there is probable cause to detain him if he will undergo a "significant pretrial restraint on liberty"—more than the mere condition that he return for trial. This hearing, while constitutionally required if these conditions are met, need not be adversary and does not give rise to a right to counsel. As with the hearing to obtain an arrest warrant, this proceeding does not even require the accused's presence. The standard of proof is simply whether there is probable cause to believe the suspect has committed a crime.
The search context is the second major area in which the issue of probable cause arises. Most courts hold that probable cause for a search exists when the facts and circumstances in a given situation are sufficient to warrant a man of reasonable caution to believe that seizable objects are located at the place to be searched. (See brinegar v. united states; carroll v. united states.)
The probable cause determination is generally based on the information supplied to the magistrate in the application for a search warrant. An application must be sworn to and must allege the place to be searched, the property to be seized, the person having the property if it is to be taken from his control, and the underlying crime. There is no requirement that everything must be set out in the application itself; affidavits may be attached or sworn statements taken before the magistrate. Because applications are usually submitted by police officers who do not have legal training, the language of the application is to be construed in a nontechnical way. Nevertheless, if the application is all that is submitted, and it is expressed in "conclusory" terms only, it will be insufficient to establish probable cause. Sufficient data must be contained in either the application itself or the supporting affidavits to justify the magistrate in issuing the warrant.
Although no blanket assertion can explain all cases involving probable cause for the issuance of search warrants, one useful rule of thumb is that if the affidavit and supporting documents allege facts that can explain to the magistrate the basis for the probable cause determination, a warrant based on such an affidavit is likely to be good. On the other hand, when an affidavit asserts a mere conclusion such as "we have it on good information and do believe there are drugs at the suspect's home," there is no independent basis for the magistrate's determination. A warrant based on such a showing is likely to be invalid.
The hardest issue arises when the affiant police officer is not the source of the information but is relying on an informant. Most of the Supreme Court's decisions concerning the required credibility of informants have arisen in cases involving search warrants rather than arrest warrants, but the standards for use of informants in both contexts are the same.
The Supreme Court first enunciated the requirements for a valid informant-based warrant in aguilar v. texas (1964). According to this test, the affidavit must: (a) set forth sufficient underlying circumstances to demonstrate to a neutral and detached magistrate how the informant reached hisher conclusion; and (b) establish the reliability or credibility of the informant. In the subsequent case, spinelli v. united states (1969), the Supreme Court explained that the absence of a statement detailing the manner in which the informant's data were gathered renders it especially important that "the tip describe the accused's criminal activity in sufficient detail that the magistrate may know that he is relying on something more substantial than a casual rumor … or an accusation based merely on an individual's general reputation."
The Aguilar/Spinelli test has, however, been rejected by illinois v. gates (1983). The Court in Gates introduced a totality-of-the-circumstances test, stating that it was not necessary to establish the credibility of the informant as a separate element to a valid search warrant. Instead, reliability and credibility of the informer and his basis of knowledge are considered as intertwining considerations that may illuminate the probable cause issue. In Gates the police received an anonymous informant's letter containing details of the defendants' involvement in drug trafficking which were corroborated by police investigations. The Court held that this provided a sufficient basis for a finding of probable cause.
Finally, according to Henry v. United States (1959), if the police had probable cause to arrest or search, the fact that the information on which they relied turns out to be false does not invalidate the arrest or search. Sufficient probability is the touchstone of Fourth Amendment reasonableness.
(See preliminary hearing.)
Charles H. Whitebread