11th Circ. Puts Spotlight On Warrantless Cellphone Search

March 4, 2015Articles Law360

Reprinted with permission from Law360. (c) 2014 Portfolio Media. Further duplication without permission is prohibited. All rights reserved.

It is safe to say that cellphones are one of the most revolutionary devices of our time. We can’t leave home without them. Mental health professionals are studying their addictive properties. They were once a luxury item, now they are viewed as a necessity. They have physically evolved from massive devices that required their own carrying cases and large, obtrusive, boom-like antennas, to the sleek, touchscreen mini-computers that have changed the way that we live, work and play forever. Their ubiquity and their impact upon our culture are undeniable. They are such an instrumental part of our lives that it is difficult to remember what life was like without them.

As with any society-shaping phenomenon, the legal issues that have developed alongside the mobile telephone’s meteoric rise to prominence in modern society are numerous. One such issue — the warrantless seizure of cellular tower data — may very well be about take center stage.

What Is Cellular Tower Data?

All kinds of data are created by your cellphone, whether you like it or not. The fact of the matter is that discoverable data is produced even when a subject is not talking, texting, or checking in on social media. Cellular tower data is a byproduct of the communications between a user’s mobile device and the service provider’s network infrastructure that supplies the wireless voice and data services for the device.

Scott Johnson is the manager of the computer forensics and e-discovery practice for the CohnReznick Advisory Group. Before he held that role, he was a lieutenant in the New Jersey State Police, assigned as the deputy director of the New Jersey Regional Computer Forensics Laboratory, an FBI task force composed of local, county, state and federal law enforcement officers on the front lines of efforts to combat high-tech criminal activity in the modern digital landscape. He describes tower data as “housekeeping radio traffic” with the service provider’s geographically fixed towers. According to Johnson, this radio traffic is recorded by the cellular service provider, and can be of use in calculating the approximate location of a given handset or SIM card at a given point in time, provided only that the device is turned on. According to Johnson, in the modern cellular infrastructure, the ideal scenario for cellular providers would be for towers to be placed to create arrays of cellular antennas in a roughly hexagonal pattern across the city or countryside, with a tower optimally at the conversion point of any three sides of identical adjacent hexagons, providing complete, seamless coverage areas.

In reality, Johnson explains, the network’s coverage requirements and the nuances of the topography like terrain, obstructions, altitude and radio interference from other transmitting sources dictate that geometrically perfect, hexagonal patterns cannot be practically maintained. Since effective communication distances vary from tower to tower, even from antenna to antenna on a single tower, no single geometric shape can be assigned to an individual cell tower’s coverage area. Thus, the data derived from interactions between device and network infrastructure is not as precise as, for example, GPS coordinates.

The supposed evidentiary value of cell tower data is derived from what Johnson describes as “some consistent facts about cellular technology.” Initially, every tower is at a known, geolocated position and records the relative signal strength of every handset with which it communicates. This data is used to help the provider monitor the quality of its services, among other things. Armed with this data, Johnson explains, “very approximate distances between the handset and the cell tower can be calculated by engineers using varied combinations of signal strength and round-trip travel time for the radio signal.”

The approximate location of the mobile device can then be attempted by evaluating a host of qualitative and quantitative factors in an exercise of triangulation that is akin to attempting to deconstruct pea soup. Johnson lists these variables as: (1) the known locations of three or more towers; (2) the compass direction of the antennas; (3) their approximate distances from the handset; and (4) changing signal strengths.

An analysis of the data rich environment associated with cell towers is not limited to attempts at identifying the possible location of a user either. This information can also be used, in some circumstances, to identify device type, the identity of the user, and whatever else a provider maintains about its customers. In short, this data is a gateway to a mobile phone user’s digital life. Once unlocked, it is an open book. In addition to the very obvious privacy considerations, cellphone tower data presents a unique constitutional dilemma that typifies the significant lag between technological advances and jurisprudential progress.

The Constitutional Debate

In United States v. Jones, 132 S.Ct. 945 (2012), the United States Supreme Court held, in a rare unanimous decision, that it was a violation of the Fourth Amendment of the United States Constitution to connect a GPS tracking device to a suspect’s vehicle without a warrant. Jones fell short of conclusively answering all of the open questions presented as a consequence of the dramatic technological expansion over the past 20 years, and the warrantless use of cell tower data is one of them.
The federal government has frequently taken the position that it does not need to obtain a warrant before obtaining and utilizing tower data as part of an investigation, distinguishing its conduct in a warrantless cell tower data grab from the use of prohibited GPS tracking.

In support of its position, the feds rely upon the so-called “third party doctrine” that emerged from the United States Supreme Court’s decision in Smith v. Maryland, 442 U.S. 735 (1979), stating that there is no legitimate expectation of privacy in information that an individual voluntarily makes available to others under circumstances where they did not have to do so, yet made a volitional choice to do so anyway. Smith involved the installation of a “pen register” to create a record of all numbers dialed by a suspect in an effort to demonstrate that he was making threatening phone calls to the alleged victim. At trial, the defendant moved to exclude the evidence derived from the pen register because the government did not secure a warrant. The Supreme Court ultimately reviewed the case and determined that no warrant was required because the defendant had no reasonable expectation of privacy in information that was voluntarily turned over to a third party, in that case, the 1970s manifestation of the landline telephone company.

The federal government has succeeded before in advancing the argument that the third-party doctrine allows it to obtain tower data without a warrant. See In re Application of U.S. for Historical Cell Site Data, 724 F.3d 600 (5th Cir. 2013). However, last year, a panel of judges from the Eleventh Circuit Court of Appeals weighed in on the topic, refusing to adopt the same position. See United States v. Davis, 754 F.3d 1205 (11th Cir. 2014). The Eleventh Circuit panel initially held that a warrant was required, but the government then moved for rehearing en banc, and the government’s motion was granted. Oral argument before the full Eleventh Circuit Court of Appeals was held on Feb. 24 in Atlanta. A decision is expected later this year.

In Davis, the government obtained tower data from the cellphones of four people over a 67-day period in connection with an investigation into an armed robbery spree. Investigators did so without a search warrant. The data was obtained under a provision in the federal Stored Communications Act that allows the government to get a court order for such information without showing probable cause. Davis, 19 years old at the time, was convicted and ultimately sentenced to nearly 162 years in prison on the strength of the evidence secured by the government against him. A first-time offender, he received a life sentence on the strength of a warrantless search. His fate currently rests in the hands of a court that has already once declared the government’s conduct unconstitutional. However, even if the en banc panel once again sides with Davis, this does not appear to be an issue that is going away anytime soon.

According to reports from oral argument, Davis’ attorney, David Markus, began by describing the historical evolution of the cellphone as a microcosm for the lag often found between technology and the law. Foreshadowing Davis’ potential journey to the docket of the United States Supreme Court, Markus reportedly invoked the commentary of Chief Justice John Roberts in Riley v. California, 134 S.Ct. 2473, the recent decision of the Supreme Court unanimously requiring a warrant to search the contents of a cellphone. In that landmark decision, the Chief Justice wrote of cellphones, “[they] are now such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy."

The Road Ahead

Conventional wisdom dictates that the Eleventh Circuit granted leave for en banc review in Davis because of the importance of this issue, and the circuit split with the Fifth Circuit that would emerge as a consequence of a decision in favor of Davis. Increasing numbers of states are also interpreting their own constitutions to require a warrant to gather tower data, in what should signal an evolving standard of conduct for law enforcement. Should the Eleventh Circuit affirm the earlier panel decision requiring a warrant, the stage will be set for the matter to be reviewed by the United States Supreme Court, as the resulting circuit split would make the case ripe for certiorari to the highest court in the land.

In what can only be described as dramatic, AT&T, one of the largest wireless providers in the United States, has appeared as one of several amici in Davis that advocate for a warrant requirement for tower data. AT&T’s counsel frames its argument in response to the government’s reliance upon the third-party doctrine succinctly: “Nothing in Smith or Miller [the United States Supreme Court’s third-party doctrine jurisprudence] requires that individuals must choose between participating in the new digital world through use of their mobile devices and retaining the Fourth Amendment’s protections.” (AT&T’s Amicus Br. at pp. 20-21).

We are constantly evolving as a society — it is a necessary adaptation that ensures the long term stability of our nation. The United States Constitution was signed by the delegates to the Constitutional Convention on Sept. 17, 1787. The commercial Internet, by most accounts, did not come onto the scene in its present form until the mid-1990s, and the iPhone, the hands down most popular mobile device in the nation, did not make its debut until June 29, 2007. If the right of the people to be secure in their persons, houses, papers and effects against unreasonable searches and seizures is to have any meaning in the modern digital world, the government should be required to secure a warrant before being able to secure cell tower data.

Reprinted with permission from Law360. (c) 2014 Portfolio Media. Further duplication without permission is prohibited. All rights reserved.