Sometimes a person arrested for a crime will swear he or she was nowhere near the location when the criminal incident took place., but the prosecution will allege otherwise…with evidence to prove it. That evidence: tracking of the defendant’s cell phone. Even if the defendant wasn’t using his or her cellphone at the time, the cellphone sends data to cell towers, or more commonly these days, the GPS system embedded on most cellphones does the work. All the police need is the defendant’s cellphone (assuming he or she was carrying it at the time of the alleged crime) to find the defendant’s location at the time. But what if the cellphone, say, disappeared? The authorities can still get the information from the cellphone service provider.
In California, the state authorities need a warrant (or the cellphone owner’s consent) to search any cell phone data, but that isn’t true in all states and it isn’t the case for federal crimes. So even if an individual is suspected of a crime in California, but it is a federal crime being investigated by federal authorities, those authorities do not need a warrant to search historical data held by the suspect’s cellphone service provider.
The Fourth Amendment to the United States Constitution guarantees that every person in this country is secure from unreasonable searches and seizures. How “unreasonable” is defined is the subject of many a treatise but for purposes here and ignoring the enumerated exceptions for the moment, if there is no warrant, the search and seizure is considered by law to be “unreasonable.” How would the warrantless search of historical cellphone data as recorded by the cellphone service provider fit into the cellphone owner’s Fourth Amendment guarantee?