Peter A. Crusco
Peter A. Crusco (NYLJ/Rick Kopstein)

Advancements in communications technology all but guarantee that Fourth Amendment issues will continue to be the subject of intense litigation as that new technology is employed by criminals and subject to surveillance by law enforcement. From automobile black boxes and GPS devices to IP surfing surveillance, courts have weighed in on the constitutional implications of law enforcement surveillance involving advanced technologies.1 This article will address another communications technology enhanced tool—the “cell tower dump”—and its Fourth Amendment implications, which the U.S. Supreme Court has yet to resolve.

The Cell Tower Dump

In the usual case, a cell tower dump is utilized by law enforcement to assist in the identification of cellular telephones in use near a specified location on a certain date and time. This is to be contrasted with the more routine request for cellular telephone usage otherwise known as cell site location information (CSLI) or call detail for a particular identified cellular telephone, that is, a request for dialed digits consisting of calls to and from the telephone number with the locations and sectors of the cell towers through which each call originated and terminated.2 CSLI assists in determining the general locations of the cellular telephone, and aids in identifying the suspect using the phone.3 In a cell tower dump, the specified location is identified by the cell towers in the area of the location. The suspect phone is usually unknown. The cell tower dump information results in the identification through cellular service provider records of all the cellular telephones that were somewhere in the vicinity of the particular cell tower on the date and time in issue, resulting in data that may generate additional leads or evidence depending on the scope of the matter under investigation.4 For instance, in one high profile case, the FBI obtained cell tower dump records corresponding to the area and time of a dozen bank robberies by the so-called “Scarecrow Bandits” who had victimized banks in the Dallas area. These tower dump records reflected the cellular telephones using the cell tower closest to the banks at the time of the robberies. These extensive records showed several of the defendants’ cellular telephones which used those cell towers at or around the time of each robbery. Moreover, there were also numerous calls between other members of the robbery crew under investigation that were linked to the two main defendants, as well as to the cell tower near the banks that were robbed.5 The data from the cell tower dumps was crucial in bringing to justice the entire bank robbery crew. In another case, Matter of D.O. v. D.O.,6 police obtained a search warrant for defendant’s Facebook data based upon information received from a cell tower dump, which disclosed that defendant’s cell phone was near three burglary sites at the same date and time the burglaries occurred. The tower dump, the Facebook data and information supplied by an informant further corroborated defendant’s involvement in the burglaries.

Cellular telephone service carriers reported that they complied with over 9,000 cell-tower dump requests by law enforcement nationwide in 2013. These requests typically covered time periods of less than 30 minutes where law enforcement was able to pinpoint the approximate date and time of the crime or suspect event. Carriers keep cell phone data for differing periods of time, including anywhere from as long as five years to as brief as 180 days, depending on the carrier’s policy. Carriers annually earn millions of dollars processing the data requests by law enforcement.7

Stored Communications Act

The debate concerning the disclosure of cell tower dump records to law enforcement concerns the legal standard required by the courts that law enforcement must satisfy before a cellular service provider is required to make disclosure. The ostensible statutory authorization for the cell phone dump is the Stored Communications Act (SCA), 18 U.S.C. §2703. Section 2703(d) does not require the warrant standard of probable cause, but instead a lesser showing of specific and articulable facts demonstrating reasonable grounds to believe that the records or other information sought are relevant and material to an ongoing investigation.8

Fourth Amendment Implications

Defendants, legislators and privacy groups have contended that privacy laws need updating and urge changes requiring that law enforcement obtain probable cause warrants before cellular service providers disclose certain cell phone records. There are three frequent arguments against the application of the §2703(d) standard to cell tower dumps. The first is that §2703(d) requires the government satisfy the “reasonable suspicion” standard in a telephone dump scenario where there may be no individualized suspicion as to a known cell phone. This argument has had little traction as the standard of reasonable suspicion akin to a Terry or DeBour street encounter stop is not that specifically required by a §2703(d) order.9

A second argument, the warrant argument, is that the information sought by a cell tower dump requires that the government meet the warrant standard of probable cause as per the Fourth Amendment to the U.S. Constitution. The warrant argument is two-fold: First the probable cause standard must be satisfied, and second, the data sought by a cell tower dump contravenes the Fourth Amendment’s prohibition against “dragnet surveillance.” Both arguments are addressed below.

Initially, we start with the axiom that the fundamental purpose of the Fourth Amendment of the U.S. Constitution “is to safeguard the privacy and security of individuals against arbitrary invasions by government officials.”10 The Fourth Amendment provides in relevant part that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated.”11

The Fourth Amendment does not guarantee against all searches and seizures, only those that are unreasonable.12 In order for the protection of the Fourth Amendment to be invoked under the Katz test, an individual asserting a violation thereof must satisfy a twofold test: first that the person has exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as “reasonable.”13 In determining whether an expectation of privacy is reasonable, one must look to “a source outside of the Fourth Amendment, either by reference to concepts of real or personal property law or to understandings that are recognized and permitted by society.”14

Third-Party Doctrine

The warrant argument against the application of the §2703(d) standard to cell tower dumps is usually countered by the government with the “third-party doctrine” first articulated in a pre-cellular world in 1979 in the U.S. Supreme Court case, Smith v. Maryland.15 There the high court held that a defendant did not have a reasonable expectation of privacy in the telephone numbers he dialed on the telephone, even after that information was automated by the telephone company, or as the court stated: “A person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.”16 More recently, in 2012 the U.S. Court of Appeals for the Sixth Circuit in United States v. Skinner17 compared cell phone technology to giving the numbers to a telephone operator, where they would not be confidential. The court stated that similar reasoning compelled the conclusion that Skinner did not have a reasonable expectation of privacy in the location of his cell phone while traveling on public thoroughfares. The third-party doctrine enunciated in Smith v. Maryland was followed by the New York Court of Appeals in People v. Guerra.18

In 2012, the U.S. Supreme Court in United States v. Jones19 invalidated the warrantless use of a GPS device on defendant’s automobile. There the police secretly placed a GPS tracking device on defendant’s vehicle, which was found to be a physical intrusion into a constitutionally protected area as per the “trespassory test.” The court also opined that such test provides little guidance in cases of “electronic or other modes of surveillance that do not depend upon a physical invasion on property.”20 For those cases, Katz would continue to apply. The court also stated that situations involving merely the transmission of electronic signals without trespass would remain subject to the Katz analysis.

The third-party doctrine is under intense scrutiny today in both state and federal courts. Some courts have determined that the doctrine is inapplicable to cell phone location data because the telephone subscriber does not voluntarily convey their location information to their own cellular service provider in the sense that one first identifies a discrete item of information or data point like a telephone number or a check or deposit slip and then transmits it to the provider. 21 Recently, appellate courts in New Jersey and Pennsylvania have rejected the third-party doctrine, finding instead that their own state constitutions provides their citizens with greater privacy protections and that the cell phone service provider’s ability to access cell site location information did not “translate into a waiver of an expectation of privacy.”22

Tower dumps have also been attacked on the basis that they are a “dragnet type of surveillance” prohibited by the Fourth Amendment. The prohibition against dragnet type surveillance is gleaned from the 1983 U.S. Supreme Court decision in United States v. Knotts.23 In Knotts, the government was investigating an individual believed to be involved in the purchasing of precursor chemicals for the production of illicit drugs. Government agents placed a tracking device in a five gallon drum of chloroform with the consent of the seller of the chloroform. Defendant Knotts purchased the chloroform, and the police used the tracking device to discover the location of his clandestine drug factory. In Knotts, the Supreme Court held that the monitoring did not violate the Constitution because

[t]he governmental surveillance conducted by means of the beeper in this case amounted principally to the following of an automobile on public streets and highways … . A person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.24

Noting the fear that their holding could usher in 24-hour surveillance of any citizen without judicial knowledge or supervision, the court observed that, “if such dragnet type law enforcement practices” should eventually occur, there will be time enough then to determine whether different constitutional principles may be applicable.” The concern of ostensibly legal but overly comprehensive tracking by police in violation of the Fourth Amendment raised in Jones by Justice Samuel Alito’s concurrence is inapplicable to cell tower dumps that usually are limited to a 30-minute time period on a specific date in a specific location identified by the towers.25 Thus, the surveillance employed is not indiscriminate, infinite in nature, or pervasive, rather it is specific and finite, limited to a specific date, time and place. “Such relatively short-term monitoring of a person’s movements on public streets accords with expectations of privacy that our society has recognized as reasonable.”26

The Pinging Cases

The legality of the cell phone dump is also buttressed by cases that have held that “cell phone pinging” does not require a warrant. For instance, in United States v. Skinner, 27 the U.S. Court of Appeals for the Sixth Circuit, held that pinging a drug courier’s cell phone to identity his location did not constitute a Fourth Amendment search, determining that the target lacked a reasonable expectation of privacy under the U.S. Supreme Court’s Katz test.28 Skinner did not have a reasonable expectation of privacy in the data emanating from his cell phone, “just as the driver of a getaway car has no expectation of privacy in the particular combination of colors of the car’s paint.”29

In May 2014, a New York federal court authorized a cell tower dump request on the basis of a §2703(d) after requesting legal memorandum on the issue from privacy groups. The court also required the government to explain how it was going to secure the data the dump revealed about innocent bystanders.30

Peter A. Crusco is executive assistant district attorney, investigations division, Office of the Queens County District Attorney. The views expressed herein are the author’s, and do not necessarily reflect the policies or views of the office.


Privacy advocates, legislators and the courts are debating the legal standard concerning obtaining data from cell tower dumps. Is a §2703(d) order sufficient or is a search warrant required? The nature of the debate intensifies as technology advances and more sensitive information is available and stored by cellular telephone service providers. The debate includes what standard should be put in place for monitoring the use, retention and disposal of collateral data about innocent bystanders gleaned from cell tower dumps. All of these issues have no doubt intensified given the federal government’s NSA surveillance revelations, and has now become part of the general milieu of evolving surveillance regulation and case law.

1. See, e.g., People v. Weaver, 12 N.Y. 3d 433, 445 (2009) (warrant required for GPS device); United States v. Jones, 131 S. Ct. 3064 (2011) (warrant required for GPS device); United States v. Rigmaiden, 2013 U.S. Dist. LEXIS 65633 (fraudulent tax return investigation in which §2703(d) orders were utilized to obtain IP addresses from the defendant’s aircard surfing).

2. See, e.g., United States v. Allums, 2009 U.S. Dist. LEXIS 28276 (D. Ut. 2009) (admissibility of cellular telephone call detail records); United States v. Evans, 892 F. Supp. 2d 949 (D. Ill. 2012) (admissibility of cell site evidence and expert analysis).

3. See, e.g., People v. Hall, 86 A.D. 3d 450 (1st Dept. 2011), lv. den. 19 N.Y. 3d 961 (2012), cert. den. 133 S. Ct. 1240 (2013).

4. See In the Matter of the Application for an Order Pursuant to 18 U.S.C. §§2703(c) and 2703(d), 2014 U.S. Dist. LEXIS 76155 (S.D.N.Y. May 30, 2014, James C. Francis IV, M.J.) (titles of cases have been abbreviated due to their length and the names of the judges noted for easier reference).

5. United States v. Duffey, 2009 U.S. Dist. LEXIS 65841 *2 (N.D. Tex. 2009, Jane J. Boyle, D.J.), cert. den. Hewitt v. United States, 132 S. Ct. 2700 (2012).

6. 2013 N.D. 247 (Dec. 19, 2013).

7. See, e.g., David Kravets, “Cops and Feds Routinely ‘Dump’ Cell Towers to Track Everyone Nearby,” Wired, available at; John Kelly, “Cellphone Data Spying: It’s Not Just the NSA,” USA Today, May 20, 2014.

8. In re Application, 620 F. 3d 304, 313 (3d Cir. 2010) (§2703(d) standard is a lesser one than probable cause); United States v. Rigmaiden, 2013 U.S. Dist. LEXIS 65633.

9. See People v. DeBour, 40 N.Y. 2d 210 (1976); Terry v. Ohio, 392 U.S. 1 (1968).

10. Camara v. Mun. Ct., 387 U.S. 523, 528 (1967).

11. U.S. Const. 4th Amend.

12. See United States v. Sharpe, 470 U.S. 675, 682 (1985).

13. Katz v. United States, 389 U.S. 347, 361 (1967).

14. See, e.g., Rakas v. Illinois, 439 U.S. 128, 144 n.12 (1978).

15. Smith v. Maryland, 442 U.S. 735, 742-45 (1979) (defendant did not have a reasonable expectation of privacy in the numbers he had dialed from his telephone, because he voluntarily conveyed that information to his cellular telephone company when he placed the calls).

16. Smith v. Maryland, 442 U.S. at 743-44; see also United States v. Miller, 425 U.S. 435, 442-44 (1976) (a bank customer had no reasonable expectation of privacy in financial information that he voluntarily conveyed to the bank for it to use in the ordinary course of business.); see also United States v. Forrester, 512 F. 3d 500 (9th Cir. 2007) (involving veiled IP use/electronic surveillance per a court approved pen register order – analogue known as a “mirror port” on defendant’s Internet account). A pen register order does not require the demanding standard of “probable cause” required for a search warrant. Information obtained from a pen register trap trace on a cell phone is more detailed, automatically sent to the phone company with no “dialing” from the subscriber, and includes CSLI.

17. United States v. Skinner, 690 F.3d 772 (6th Cir. 2012), cert. den. 133 S. Ct. 2851 (2013).

18. People v. Guerra, 65 N.Y. 2d 60, 63-64 (1985); but see People v. Weaver, 12 N.Y.3d 433, 445 (2009) (court expanded New York’s constitutional protections in holding that the state Constitution, Article 1 §12, the analog to the Fourth Amendment, prohibits the government’s use of a GPS tracking device to monitor an automobile’s movements in the absence of exigent circumstances without a warrant).

19. United States v. Jones, 132 S. Ct. 945, 957 (2012) (statement of Justice Sonia Sotomayor that, in this digital age “it may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties”).

20. United States v. Jones, 132 S. Ct. 945, 955 (2012) (Sotomayor, J., concurring).

21. See also United States v. Davis, 2014 U.S. App. LEXIS 10854 (11th Cir. June 11, 2014) (CSLI data requires a warrant; subscribers have a reasonable expectation of privacy in the data); Commonwealth v. Augustine, 467 Mass. 230, 250 (2014); see also C.P.L. §705.10 (“reasonable suspicion” requirement for an application for a pen register/trap and trace device); see In the Matter of the Search of Cellular Telephone Towers, 945 F. Supp. 2d 769 (S.D. Tex. May 8, 2013, Rian Owsley, M.J.); In re U.S. ex rel. Order Pursuant to 18 U.S.C. §2703(d), 2012 WL 4717778 (S.D. Tex. Sept. 26, 2012) (Rian Owlsey, M.J.) (rejecting an application under the Stored Communications Act for records of all of the cell phone numbers in communication with four different cell towers used around the time and place of a specific crime under investigation holding that cell-site data is protected under the Fourth Amendment and compelling it therefore requires a warrant.) Courts have also denied prospective cell tracking applications on less than probable cause on the theory that such surveillance is governed by the ECPA’s section on tracking devices requiring probable cause, given the possibility of tracking occurring in a location not open to visual surveillance. See Matter of Application, 402 F. Supp. 2d 597, 604 (D. Md., 2005, Bredar, M.J.).

22. Pennsylvania v. Rushing, 2013 PA Super 162 (2013) (warrant required to track defendant’s cell phone under court’s interpretation of state constitution); State v. Earls, 214 N.J. 564, 587 (2013) (rejecting the third-party doctrine); Commonwealth v. Augustine, 467 Mass. 230 (2014) (holding that the state generally must obtain a warrant before acquiring a person’s historical CSLI records).

23. United States v. Knotts, 460 U.S. 276, 281 (1983).

24. Cf., People v. Weaver, 12 N.Y.3d 433, 445 (2009).

25. See United States v. Skinner, 690 F.3d 772 (6th Cir. 2012) (the dragnet argument was rejected in a case that only involved three days of surveillance); Cf., Berger v. New York, 388 U.S. 41 (1967) (invalidating New York’s wiretap statute for failure of specificity and other grounds).

26. United States v. Jones, 132 S. Ct. 945, 964 (2012) (Alito, J., concurring).Cf., United States v. Jones, 2012 U.S. Dist. Lexis 92129 (M.D. Ala., 2012, Wallace Capel Jr., M.J.) (the pinging of the cell phone was conducted pursuant to a search warrant); see, United States v. Forest, 355 F.3d 942 (6th Cir. 2004) (pinging the defendant’s cell phone to determine his location was not a violation of the Fourth Amendment).

27. United States v. Skinner, 690 F.3d 772 (6th Cir. 2012); see also State v. Taylor, 2014 Ohio 2550 (2014).

28. Katz v. United States, 389 U.S. 347, 351 (1967) (“For the Fourth Amendment protects people, not places. What a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection. … But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected”); Cf., United States v. Barajas, 2013 U.S. App. LEXIS 4475 (10th Cir., March 4, 2013) (pinging evidence was properly admitted in a drug trafficking case; the court assumed without deciding that pinging is a search, and although there may have not existed probable cause for pinging, the evidence was deemed admissible pursuant to the good-faith exception).

29. See, e.g., United States v. Jones, 2012 U.S. Dist. Lexis 92129 (M.D. Ala., 2012).

30. See In the Matter of the Application for an Order Pursuant to 18 U.S.C. §§2703(c) and 2703(d), 2014 U.S. Dist. LEXIS 76155; see also Matter of the Search of Information Associated With the Facebook Account, 2013 U.S. Dist. LEXIS 185850 (D.D.C Nov. 26, 2013, John M. Facciola, M.J.).