The world is now a much smaller and more surveilled place. Private companies that make our smart phones, home security systems, smart home systems, baby monitors, computers, E-Z Pass, real time traffic apps and many more internet-of-things devices track, record and store information about our personal lives. Law enforcement has access to much of this information, often without the need for a warrant. Furthermore, law enforcement has its own methods to track and record private citizens through wiretaps, license plate readers, surveillance cameras, mobile tracking devices, hidden recorders and many other devices and methods.

One recent bright spot was the United States Supreme Court’s decision in Carpenter v. United States, which held that the Fourth Amendment protects data generated by our cell phones known as historical cell site location information or CSLI. The Carpenter court acknowledged that CSLI creates a “detailed chronicle of a person’s physical presence compiled every day, every moment over years” and therefore requires the police to obtain a court-authorized warrant to obtain the information from the service provider.

CSLI is information our cell service providers record and store as our cell phones connect or ping off of each cell tower as we travel across the country. Other devices, such as our smart watches, track our daily movements through apps like Waze or Google Maps for real time traffic alerts and directions. This information, whether we knowingly agreed to it or not, is collected and saved by these providers. The question becomes whether law enforcement can access this information from third party providers without a court-authorized warrant. The Carpenter decision recognized that in certain circumstances, a person has a right to privacy even in information we share with third parties in public activities. Carpenter has now been cited in more than 450 criminal and civil cases across the country.

This expanding area of Fourth Amendment law is critical in protecting the average person’s right to privacy. When one’s daily movements can be tracked by our use of everyday devices, law enforcement should minimally have to demonstrate probable cause to a court in order to obtain a warrant for that data. Without such a safeguard, police can randomly check on anyone’s travel history, purchase history, or even voice recordings from smart home systems such as Alexa, Google Home or Echo.

This is an ever-developing and expanding area of law. It is important to hire well-versed and adept counsel when dealing with law enforcement’s intrusion into your personal data. We at Stahl Criminal Defense Lawyers aggressively defend individuals charged with complex federal and state crimes. To contact the firm, call 908.301.9001 for the NJ office and 212.755.3300 for the NYC office, or email Mr. Stahl at