Does Our Digital Age Require New Fourth Amendment Rules?

October 17, 2017 | Shari Claire Lewis | Privacy, Data & Cyber Law

It’s 10 p.m. Your cellphone knows where you are. It also knows where you are at 10:00 in the morning, at 7:00 in the evening, and at noon and midnight and at every other moment of the day.

We live in a world where cellphones are omnipresent. We have them at home, at work, and everywhere we go other than home and work. The cellphone may be the product that is more a part of our daily lives than any other.

It is perhaps no coincidence, therefore, that cellphones are at the heart of a case currently pending before the U.S. Supreme Court, Carpenter v. United States, No. 16-402, that may result in a new 21st Century standard for searches and seizures under the Fourth Amendment. If the court rejects new rules for a new age, it simply may confirm that the government’s collection of business records containing cell site location data is not a search under the Fourth Amendment, leaving cell phone users subject to the existing standard.

Carpenter’s Conviction

As the U.S. Court of Appeals explained in its decision, United States v. Carpenter, 819 F.3d 880 (6th Cir. 2016), the case arose in April 2011 when police arrested four men suspected of committing a string of armed robberies at Radio Shack and T-Mobile stores in and around Detroit. One of the men confessed that the group had robbed nine different stores in Michigan and Ohio between December 2010 and March 2011, supported by a changing group of 15 other men who served as getaway drivers and lookouts.

The robber who confessed to the crimes gave the FBI his own cellphone number and the numbers of other participants. The FBI then reviewed his call records to identify numbers that he had called around the time of the robberies.

The FBI applied for three orders from magistrate judges to obtain “transactional records” from various wireless carriers for 16 different phone numbers. As part of those applications, the FBI recited that these records included “[a]ll subscriber information, toll records and call detail records including listed and unlisted numbers dialed or otherwise transmitted to and from [the] target telephones from December 1, 2010 to present[,]” as well as “cell site information for the target telephones at call origination and at call termination for incoming and outgoing calls[.]”

The FBI also stated that these records would provide evidence that Timothy Carpenter, Timothy Sanders, and other individuals had violated the Hobbs Act, 18 U.S.C. §1951.

The magistrates granted the applications pursuant to the federal Stored Communications Act, 18 U.S.C. §2703(d), which provides that the government may require the disclosure of certain telecommunications records when “specific and articulable facts show[] that there are reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation.”

The government later charged Carpenter with six counts, and Sanders with two, of aiding and abetting robbery that affected interstate commerce, in violation of the Hobbs Act, and aiding and abetting the use or carriage of a firearm during a federal crime of violence.

Before trial, Carpenter and Sanders moved to suppress the government’s cell site evidence on Fourth Amendment grounds, arguing that the records could be seized only with a warrant supported by probable cause. The district court denied the motion.

At trial, seven accomplices testified that Carpenter typically waited in a stolen car across the street from the targeted store and that, at his signal, the robbers entered the store, brandished their guns, herded customers and employees to the back, and ordered the employees to fill the robbers’ bags with new smartphones. After each robbery, the team met nearby to dispose of the guns and getaway vehicle and to sell the stolen phones.

An FBI agent offered expert testimony regarding the cell site data provided by Carpenter’s and Sanders’s wireless carriers, MetroPCS and T-Mobile. The agent explained that cellphones work by establishing a radio connection with nearby cell towers (or “cell sites”); that phones are constantly searching for the strongest signal from those towers; and that individual towers project different signals in each direction or “sector,” so that a cellphone located on the north side of a cell site will use a different signal than a cellphone located on the south side of the same tower. The agent added that cell towers typically are spaced widely in rural areas, where a tower’s coverage might reach as far as 20 miles. In an urban area like Detroit, however, each cell site covers “typically anywhere from a half-mile to two miles.” The agent testified that wireless carriers typically log and store certain call-detail records of their customers’ calls, including the date, time, and length of each call; the phone numbers engaged on the call; and the cell sites where the call began and ended.

With the cell site data provided by the wireless carriers, the FBI agent created maps showing that Carpenter’s and Sanders’s phones were within a half-mile to two miles of the location of each of the robberies around the time the robberies happened.

The agent used MetroPCS call-detail records, for example, to show that Carpenter was within that proximity of a Detroit Radio Shack that was robbed around 10:35 a.m. on Dec. 13, 2010. Specifically, MetroPCS records showed that at 10:24 a.m. Carpenter’s phone received a call that lasted about four minutes. At the start and end of the call, Carpenter’s phone drew its signal from MetroPCS tower 173, sectors 1 and 2, located southwest of the store and whose signals point north-northeast. After the robbery, Carpenter placed an eight-minute call originating at tower 145, sector 3, located northeast of the store, its signal pointing southwest; when the call ended, Carpenter’s phone was receiving its signal from tower 164, sector 1, alongside Interstate 94, north of the Radio Shack.

The agent provided similar analysis concerning the locations of Carpenter’s and Sanders’s phones at the time of a Dec. 18, 2010 robbery in Detroit; a March 4, 2011 robbery in Warren, Ohio; and an April 5, 2011 robbery in Detroit.

The jury convicted Carpenter and Sanders on all of the Hobbs Act counts and convicted Carpenter on all but one of the gun counts. The district court sentenced Carpenter to 1,395 months’ imprisonment and Sanders to 170 months’ imprisonment. They appealed to the Sixth Circuit, challenging the district court’s denial of their motion to exclude their cell site data from the evidence at trial.

The Sixth Circuit’s Decision

The circuit court affirmed.

In its decision, the Sixth Circuit explained that, in cases involving an asserted privacy interest in information related to personal communications, federal courts have ruled that although the content of the personal communications was private, the information necessary to get those communications from one point to another was not. In this case, the circuit court pointed out, the cell site data took the form of business records created and maintained by Carpenter’s and Sanders’s wireless carriers: When they made or received calls with their cellphones, the phones sent a signal to the nearest cell-tower for the duration of the call, and the providers made records, for billing and other business purposes, showing which towers each defendant’s phone had signaled during each call.

The circuit court ruled that these business records said “nothing about the content of any calls.” Rather, they included routing information that the wireless providers gathered in the ordinary course of business. The cell site data, the circuit court found, was information that facilitated personal communications and was not part of the content of those communications themselves. The Sixth Circuit then held that the government’s collection of business records containing this location data was “not a search” subject to the Fourth Amendment’s warrant requirements.


It remains to be seen how the Supreme Court will decide Carpenter. It could affirm on the basis of the Stored Communications Act, concluding that the issue already has been settled by Congress and that rapidly changing and pervasive technologies do not necessarily require new rules for purposes of the Fourth Amendment. Perhaps, the court could reason, Carpenter would have avoided any problem if he simply had left his phone at home.

Alternatively, it may decide that Carpenter had an expectation of privacy in the locational information obtained by the government, even though every cellphone user should know by now that a cellphone “exposes” its location to the nearest cell tower and, therefore, to the company that operates the tower. If the court were to reach this conclusion, it would bring locational data closer to the GPS monitoring information at issue in United States v. Jones, 132 S.Ct. 945 (2012), where the government secretly attached a GPS device to the underside of the defendant’s vehicle and then monitored his movements continuously for four weeks.

The court might find that the extent of the government’s search—127 days of locational records for Carpenter—went too far and implicated the Fourth Amendment for that reason alone. Whether the court would be willing to carve out an exception for business records that involve extensive locational information, but not for credit card or bank records, remains to be seen.

Another possibility is that, to overturn Carpenter’s conviction, the court instead could rely on—or, more precisely, extend—Riley v. California, 134 S.Ct. 2473 (2014), where it held that the government could not access a smartphone’s internal data without a warrant.

Stay tuned.

Reprinted with permission from the October 17, 2017 issue of the New York Law Journal. © ALM Media Properties, LLC.  Further duplication without permission is prohibited.  All rights reserved.

Related Publications

Legal updates and news delivered to your inbox