Search Warrants and Probable Cause

A judge will issue a warrant if the police can show that it's reasonably likely that the search will turn up contraband or evidence of a crime.

A search warrant is an order signed by a judge that authorizes police officers to search for particular objects or materials at a specified location and time. For example, a warrant may authorize the search of “the premises at 11359 Happy Glade Avenue between the hours of 8 a.m. to 6 p.m.,” and direct the police to search for and seize “cash, betting slips, record books, and every other means used in connection with placing bets on horse races and other sporting events.” Police officers can take reasonable steps to protect themselves when conducting a search, such as handcuffing occupants while searching a house for weapons (Mena v. City of Simi Valley, U.S. Sup. Ct. 2005).

How Officers Obtain Search Warrants

Police officers obtain warrants by providing a judge or magistrate with information that the officers have gathered. Usually, the police provide the information in the form of written statements under oath, called affidavits, which report either their own observations or those of private citizens or police undercover informants. In many areas, a judicial officer is available 24 hours a day to issue warrants.

A magistrate who believes that an affidavit establishes “probable cause” to conduct a search will issue a warrant (see the section just below for more on probable cause). The suspect, who may be connected with the place to be searched, is not present when the warrant is issued and therefore cannot contest whether there is probable cause before the magistrate signs the warrant. However, the suspect can later challenge the validity of the warrant with a pretrial motion

Police officers can also obtain an anticipatory search warrant—a warrant that issues before contraband arrives at the location to be searched—if they can show probable cause (U.S. v. Grubbs, U.S. Sup. Ct. 2006). For example, if the police demonstrate to a magistrate that illegal drugs are about to be shipped to a suspect’s home, they can get a warrant that allows the police to search the home once the drugs are delivered.

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.

Talk to a Lawyer

Start here to find criminal defense lawyers near you.

How It Works

  1. Briefly tell us about your case
  2. Provide your contact information
  3. Connect with local attorneys