Information Needed to Establish Probable Cause
The Fourth Amendment doesn’t define probable cause. Its meaning remains fuzzy. What is clear (after 200 years of court interpretations) is that the affidavits police officers submit to judges have to identify objectively suspicious activities rather than simply recite the officer’s subjective beliefs. The affidavits have to establish more than a suspicion that criminal activity is afoot, but do not have to show proof beyond a reasonable doubt.
The information in an affidavit need not be in a form that would be admissible at trial. (For example, a judge or magistrate may consider hearsay evidence that seems reliable, even if a judge might exclude it at trial.) However, the circumstances set forth in an affidavit, viewed as a whole, should demonstrate the reliability of the information (Illinois v. Gates, U.S. Sup. Ct. 1983). In general, when deciding whether to issue a search warrant, a judge or magistrate will likely consider information in an affidavit reliable if it comes from any of these sources:
- a confidential police informant whose past reliability has been established or who has firsthand knowledge of illegal goings-on
- an informant who implicates himself or herself as well as the suspect
- an informant whose information appears to be correct after at least partial verification by the police
- a victim of a crime related to the search
- a witness to the crime related to the search, or
- another police officer.
Example: Hoping to obtain a warrant to search Olive Martini’s backyard, a police officer submits an affidavit to a magistrate. The affidavit states that “the undersigned is informed that Olive operates an illegal still in her backyard.” The magistrate should not issue a search warrant based on this affidavit. Because the affidavit is too vague and the source of the information is unstated, there’s no way for the magistrate to evaluate its reliability. The affidavit doesn’t establish probable cause.
Example: Same case. The affidavit states that “I am a social acquaintance of Olive Martini. On three occasions in the past two weeks, I have attended parties at Martini’s house. On each occasion, I have personally observed Martini serving alcohol from a still in Martini’s backyard. I have personally tasted the drink and know it to be alcoholic. I had no connection to the police when I attended these parties.” This affidavit is reliable enough to establish probable cause for issuance of a warrant authorizing the police to search Martini’s backyard. The affidavit provides detailed, firsthand information from an ordinary witness (without police connections) that indicates criminal activity is taking place.
This article was excerpted from The Criminal Law Handbook, by Paul Bergman, J.D., and Sara J. Berman, J.D.