When the Bill of Rights was ratified nearly 240 years ago, it included the Fourth Amendment’s guarantee of the right of the people to be “secure in their persons, houses, papers, and effects, against unreasonable searches and seizures,” with the assurance that “no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”
Courts continue to examine what those words mean with respect to arrests, warrants, and searches. Earlier this year, the U.S. Supreme Court issued two opinions relating to police searches under the Fourth Amendment. One addressed the emergency aid exception to the warrant requirement. The other addressed a “geofence warrant” used to collect cell phone data to solve a crime.
Emergency Aid Exception
In Case v. Montana, the Court reviewed the emergency aid exception, which allows police to enter a home without a warrant when they have an objectively reasonable basis to believe someone inside needs help. As part of its analysis, the Court considered whether evidence of a crime discovered while providing emergency assistance can be used against the person being helped.
In this situation, police had genuine reason to believe Case, who was alone in his home, was a threat to himself and needed immediate assistance, so they entered his home without a warrant. When the officers found him hiding in a closet, Case appeared to be holding a gun. Fearing for his life, one of the officers shot and injured Case. Officers discovered a gun next to Case, and he was charged with assaulting a police officer.
Case argued that evidence found inside his home should be thrown out because the police entered without a warrant. The Court disagreed, affirming that an officer can enter a home without a warrant as long as the officer has “an objectively reasonable basis for believing” the entry is needed to provide emergency aid. However, the Court cautioned that officers entering a home without a warrant for emergency aid purposes are not allowed to search a home more than necessary to deal with the emergency and maintain officers’ safety.
Because the officers objectively believed they needed to enter Case’s home to provide emergency aid, and because the evidence supporting the assault charge against Case was obtained as part of the process of locating him so the officers could provide emergency aid, the officers’ entry into Case’s home without a warrant and their use of the evidence against him did not violate the Fourth Amendment.
Geofence Warrants
In Chatrie v. United States, the U.S. Supreme Court examined whether a “geofence warrant,” which allows police to virtually search a specific geographic area using technology, violated the Fourth Amendment when it was used to solve a bank robbery.
After the robbery, police obtained a geofence warrant requiring Google to share location data about cell phones that were near the bank at the time of the robbery. Google compiled this data from users’ location history, which recorded the location of users’ cell phones every two minutes. The warrant established a process through which the police narrowed an anonymous list of cell phone users in the area at the time of the robbery down to three people. The police obtained a warrant to search the home of one of them, Chatrie, and found evidence linking him to the bank robbery. At trial, Chatrie argued that the warrant violated his Fourth Amendment rights and that law enforcement should not be able to use evidence obtained from that warrant against him.
The key question was whether getting location data from Google counted as a Fourth Amendment search. The Court considered whether cell phone users have a reasonable expectation of privacy of their location data—noting it was voluntarily shared with Google-or whether cell phone users give up that expectation by voluntarily sharing their data with Google. The Court reasoned that cell phone users shouldn’t be viewed as agreeing to have their information shared with the government simply because they use their phones the way people normally use cell phones. Ultimately, the Court determined that the geofence warrant was a Fourth Amendment search because cell phone users have a reasonable expectation of privacy in their location data.
The Court, however, did not declare the search unlawful but instead sent the case back to the Court of Appeals to examine whether there was probable cause to support the search and determine if each step in the search was reasonable under the Fourth Amendment.
For city officials and police departments, the takeaways are practical. Officers responding to an emergency may enter a home without a warrant when there is an objectively reasonable basis to believe someone needs immediate help, but any search must stay within the scope of that emergency. And because courts treat requests for cellphone location data as searches, departments should expect those requests to meet full Fourth Amendment standards, including probable cause and reasonable limits at each step. Cities may want to review their policies and officer training with their city attorney in light of both decisions.
