March 2013Volume 14Number 3PDF icon PDF version (for best printing)

The new age of privacy: A surprising amount of personal information may already be available to prosecutors

Within the past week, you have likely told somebody what time you leave home in the morning, what route you take to get to work, how long it takes you to arrive, and how long you stay. If you took an extra long lunch break one day, sent a few text messages to friends or family, or made a quick stop somewhere on the way home, you probably told somebody about that, too, even if you never actually said a word about any of that to anybody. Thanks to the staggering amount of information your cell phone generates, collects, stores, and transmits, even when you aren’t using it, silence has never been more deafening.

What’s more, depending on how courts respond to these new ways of gathering information, any of this information could be used against you in a court of law.

Modern phones not only connect callers, but transmit and store information in the form of text messages and e-mails. Social media applications tell anonymous data compilers about your interests and identify your friends and family. By analyzing data transmitted to nearby cell phone towers, law enforcement officials can locate a cell phone and trace its movements over time, and more recent GPS technology, which has become increasingly commonplace, has further refined location capabilities to pinpoint accuracy.

These recent technological innovations have already proven to be a boon for prosecutors. In People v. Leak, 398 Ill.App.3d 798 (2010), for example, the prosecuting State’s Attorney confronted a defendant who claimed that he had been at his girlfriend’s home, 50 blocks away from the scene of the crime, with cell site records showing that the defendant’s cell phone was hitting a cell tower in the area where the victim was murdered. In People v. Reno, 2011 Ill.App. Unpub. LEXIS 2189 (2nd Dist. 2011), prosecutors used a detailed call log containing cell tower information, later admitted as exhibits under the business records hearsay exception, to identify the defendant’s location to within a five-mile radius. In both cases, the defendants were convicted, and both convictions were upheld on appeal, demonstrating the potential utility of this new source of data for prosecutors and law enforcement officials.

While the use of cell phone surveillance in cases such as Leak and Reno may be significant and helpful, it is hardly novel. In response to a congressional inquiry, cell phone carriers reported that in 2011, they responded to 1.3 million law enforcement demands seeking text messages, caller locations, and other information. These requests came not only from federal and state prosecutors investigating large-scale financial crimes, but also from “run-of-the-mill street crimes” handled by local police departments.1 With this exponential increase in reliance upon cellular data, cell phone surveillance is rapidly becoming one of the more useful—and used—tools in the prosecutor’s arsenal.

Whether such practices are constitutionally acceptable, however, remains a matter of contention in the legal arena. The modern understanding of the privacy interests protected under the Constitution is largely a product of cases from decades ago, involving technology that is just as old. In Katz v. U.S., 389 U.S. 347 (1967), the Supreme Court decided that after shutting the door to a private telephone booth, an individual was entitled expect that “the words he utters into the mouthpiece will not be broadcast to the world,” and that law enforcement officials were therefore required to obtain a warrant before using wiretap devices. In Smith v. Maryland, 442 U.S. 735 (1979), on the other hand, the Court held that the warrantless use of a device which recorded the numbers dialed from a particular phone in no way offended any constitutional interests, reasoning that individuals have no expectation of privacy in the numbers that they knowingly convey to the phone company. Years later, in U.S. v. Knotts, 460 U.S. 276 (1983), the Court approved of the warrantless use of a “beeper” device which allowed a following car to track the beeper from a short distance, reasoning that a person travelling in public has no legitimate expectation of privacy in his movements. The Court nevertheless declined to extend that reasoning further in a case it heard the next year, U.S. v. Karo, 468 U.S. 705 (1984). There, the Court held that the use of a beeper device on an item stored within a private residence not opened to visual surveillance violated the Fourth Amendment because it violated the expectation of privacy an individual enjoys in the confines of his own home.

Thus it was on the basis of pen registers, phone booths, and beepers that the Court decided these landmark cases. But technology has made rapid and significant developments since then, rendering the formerly state-of-the-art devices upon which the Court based its decisions obsolete. Given the amount of information that more modern devices generate and transmit—and the potential utility of that information in prosecution—it will likely be necessary to revisit the understanding of what constitutes a reasonable expectation of privacy.

But privacy law governing the prosecutor’s use of this new source of data has struggled to keep pace with developing technology. The Supreme Court’s most direct recent inquiry on the matter came in U.S. v. Jones, 132 S. Ct. 945 (2012), which presented the issue of whether law enforcement officials, without a warrant, could attach a GPS device to a vehicle, trace the vehicle’s movements over the course of several weeks, and use the information that the device generated against the individual at his trial. The Court ruled in Jones’ favor, finding no justification for the act of attaching the GPS device to the vehicle without a warrant to do so, but in doing so, left open the question of whether law enforcement officials could use GPS data to track individuals without a warrant. As such, Jones left the area of law largely unsettled.

What Jones left untouched, however, is not likely to remain so for long, as related issues have already begun to percolate through the appellate court system. In Jayne v. Blunk, 2012 U.S. App. LEXIS 20724 (9th Cir. 2012), the Ninth Circuit suggested that no warrant would be necessary for law enforcement officials to request cell phone location records from a cellular provider, because the government played no part in the generation or transmission of the GPS cell phone location data which the provider already had.2 The Sixth Circuit’s decision in United States v. Skinner, 690 F.3d 772, 778 (6th Cir. 2012), agreed, approving police use of a GPS device on “pay as you go” phone to track its user and finding “no inherent constitutional difference between trailing a defendant and tracking him via such technology.” The Second Circuit determined in U.S. v. Pascual, 2012 U.S. App. LEXIS 23272 (2nd Cir. 2012), that it was not plain error to admit cell-site records without a warrant or a showing of probable cause, and the Seventh Circuit in U.S. v. Garcia, 474 F.3d 994, 996–98 (7th Cir. 2007), held that a warrant was not required to conduct continuous electronic tracking of the defendant’s vehicle using a GPS device.

But even though the Seventh Circuit enjoys the support of many other courts in its position, the support for warrantless GPS tracking—at least, without meaningful durational limits—is not unanimous. In U.S. v. Maynard, 615 F.3d 544 (D.C. Cir. 2010), the case which would later appear before the Supreme Court as U.S. v. Jones, the DC Circuit found that prolonged GPS monitoring, and not only the mere installation of a GPS device, violated the Fourth Amendment. While other courts had approved of surveillance that lasted for only a matter of days, the Maynard court found the practically limitless duration of GPS tracking to be constitutionally unacceptable. In ruling for Jones on the issue of the installation of the device, the Supreme Court left the question of the constitutionality of the monitoring itself undisturbed. Several district courts, meanwhile, have also suggested that cell phone location data is protected under the Fourth Amendment.3 When, whether, and how the Court will resolve the tension between these cases remains to be seen.

Another recent and still-unsettled issue concerns the data found on the cellular device itself, such as text messages and e-mails. In U.S. v. Butler, 477 Fed. Appx. 217 (5th Cir. 2012), the Fifth Circuit affirmed that the warrantless search of a cell phone on the person of the defendant upon his arrest offended no constitutional interest, and thus the data obtained through that search, including text messages and call records, was admissible.4 Similarly, the Seventh Circuit approved of the warrantless search of a cell phone in U.S. v. Flores-Lopez, 670 F.3d 803 (7th Cir. 2012). Though the majority opinion authored by Judge Posner noted the great potential for an invasion of privacy in a warrantless search of a cell phone, the court nevertheless determined that there was no constitutional interest implicated, because the search was limited to finding the phone’s number, even though it could “certainly imagine justifications for a more extensive search.” Id. at 810. The Ohio State Supreme Court and judges in the Northern District of California and the District of Oregon have nevertheless disagreed with the Fifth and Seventh Circuits, citing concerns regarding the large amounts of private data cell phones may contain and ruling instead that upon seizing a phone, police must obtain a warrant to search its contents.5 Here, too, considerable disparity awaits its ultimate judicial resolution.

Rather than wait for courts to resolve the questions, some states have begun attempts to address these issues by legislative enactment, but without much result to speak of as of yet. Delaware, Maryland, and Oklahoma, for example, have all proposed legislation that would require police to obtain a warrant before demanding location records from cell phone carriers.6 Similar bills passed through the state legislatures of both California and Rhode Island, but in both states, the bills were struck down by gubernatorial veto before becoming law.7 Senator Patrick Leahy of Vermont also has proposed changes to the 1986 Electronic Communications Privacy Act which, among other things, would require law enforcement officials to obtain warrants before they can access mobile data such as e-mails and cell phone data.8 These proposed changes will merit further attention as they are discussed in committee and as they potentially make their way through the legislative process.

As these and other related issues await their resolution, whether in the courts or in the legislatures, law enforcement officials and prosecutors would do well to note the instability in this area of law, particularly as cellular surveillance becomes an increasingly indispensible tool. At present, the Seventh Circuit has looked favorably upon both the warrantless search of cell phones that lawfully come into the hands of law enforcement officials and the use of GPS tracking devices, provided compliance with U.S. v. Jones. Challenges to these positions, however, have already seen some degree of success in other courts and legislatures, and even the Seventh Circuit itself has hinted at as-of-yet undiscovered limits to its holdings. Rather than test the limits of these principles or wait and watch as support for these positions erodes beneath their feet, prosecutors and law enforcement officials may be better served by staying on more solid ground by obtaining warrants whenever they seek cellular data. Where there is no time to obtain a warrant, prosecutors may be able to use data collected over a short-term period of a few days, but warrants may be necessary as the accumulation of data becomes more extensive.

In any event, it will be necessary to watch as courts and legislatures continue their attempts to keep pace with developing technological advances. After all, the law can only lag so far behind technology for so long. ■


Patrick T. Driscoll is a Deputy State’s Attorney and Chief of the Civil Actions Bureau of the Cook County State’s Attorney’s Office in Cook County, Illinois. Douglas N. Marsh is a Special Assistant State’s Attorney in the Cook County State’s Attorney’s Office.


1. Eric Lichtblau, “More Demands on Cell Carriers in Surveillance,” N.Y. Times, June 8, 2012; available at: <> (accessed November 27, 2012).

2. See also U.S. v. Pineda-Moreno, 591 F.3d 1212 (9th Cir. 2010) (finding no constitutional violation in either the attachment of a mobile tracking device to a vehicle or its use in monitoring the defendant’s movements).

3. See, e.g., In re Application of the United States of America, 727 F. Supp. 2d 571, 582 (W.D. Tex. 2010); In re United States Order Authorizing the Release of Historical Cell-Site Info., 736 F. Supp. 2d 578, 596 (E.D.N.Y. 2010); In re United States ex rel. an Order Authorizing Disclosure of Location Info. of a Specified Wireless Tel., 849 F. Supp. 2d 526, 585 (D. Md. 2011).

4. See also U.S. v. Finley, 477 F.3d 250, 260 (5th Cir. 2007).

5. State v. Smith, 920 N.E.2d 949, 954 (Ohio 2009); U.S. v. Park, 2007 U.S. Dist. LEXIS 40596 (N.D. Cal. 2007); United States v. Hill, 2011 U.S. Dist. LEXIS 4104 (N.D. Cal. 2011); Schlossberg v. Solesbee, 844 F. Supp. 2d 1165, 1168 (D. Or. 2012).

6. Somini Sengupta, “Courts Divided over Searches of Cell Phones,” N.Y. Times, Nov. 25, 2012; available at: <> (accessed November 27, 2012).

7. Id.

8. “Senate to Reconsider Warrantless Cell Phone Searches,” Government Technology, Nov. 26, 2012, available at: <> (accessed November 27, 2012).

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