Historical cell site data: What is it, and is it protected by the Fourth Amendment?
You may have never heard of historical cell site data or cell site location information (“cell site data”). Until I started listening to the Serial Podcast, neither had I. Recently that has changed. I have now run into cell site data issues in cases ranging from Hobbs Act Robbery to Computer Fraud and Abuse Act violations over the past year. The interesting thing is that this is an emerging area of law being litigated vigorously in federal appellate courts across the country. The potential for Supreme Court review is present, but may depend on at least one very significant case from the Fourth Circuit.
A cell site is simply a cellular telephone base station or antenna where radio signals are sent and received. They come in many forms and can be found on the tops of buildings, on ridge lines or other high points throughout the country. Each tower is divided into sectors sending and collecting signals from different directions. Cell site location information, in turn, is the recorded information noting particular points in time when radio signals bounce off a given tower over a specific time frame. As a telephone call is made the cell site can change as the phone moves locations. That information is used to estimate the location of an individual by identifying the nearest cell tower and sector used while a call occurs.
In United States v. Graham, a case out of Maryland, the 4th Circuit Court of Appeals was asked to review whether collecting cell site data without a warrant violated the 4th Amendment. The case revolved around a series of robberies committed by Graham and another person in the Baltimore area. As part of the investigation, officers identified two cellphones and linked them to Graham and his accomplice. The officers requested a court order to obtain cell site data from the respective telephone companies, but never sought or obtained a warrant based on probable cause. Graham and his co-defendant were eventually charged and filed pretrial motions seeking suppression of the cell site data under the Fourth Amendment.
The Fourth Circuit, in August of 2015, found that obtaining cell site data without a warrant is an unreasonable search, but found that the good faith exception applied. However, the underlying determination that obtaining cell site data without a warrant violates the Constitution is significant. The Fourth Circuit split from other circuits in their holding. In summary, the Court found that, “the government invades a reasonable expectation of privacy when it relies upon technology not in general use to discover the movements of an individual over an extended period of time.” The Court did not define the period of time necessary to rise to the level of a violation, but considers an extended time period as including “14 or 221 days.” The Court also declined to adhere to the third party doctrine finding that because the information is transmitted as part of the regular use of the phone to cellular providers does not mean collection and inspection of the data is not a search.
The government moved for rehearing en banc, which was granted on October 28, 2015. The case was argued on March 23, 2016 and no opinion has been released. Since then, the Sixth Circuit, in United States v. Carpenter, handed down another opinion finding that obtaining cell site data without a warrant does not violate the 4th Amendment. The Fourth Circuit’s upcoming opinion is significant. If the court finds a violation then a circuit split exists increasing the chance for Supreme Court review. However, a reversal of positions by the full panel voids the potential circuit split by falling in line with the rest of the circuit courts. That would significantly decrease the chance of Supreme Court review this time. But, either way, it is worth litigating this issue in every case regardless of your Circuit’s position.
If you have a case involving cell site data it is important to move to suppress the records under the 4th Amendment, and preserve the issues for appeal even if your Circuit has ruled against your position. Eventually, this issue will be considered by the Supreme Court and if collecting cell site data requires a warrant you will be in a strong position to challenge the results in your case. You should also challenge the admissibility and reliability of the actual information if it is offered by the government through a Daubert hearing and at trial.