The Use of Cell Site Simulators Through the Lens of the Fourth Amendment

The Fourth Amendment to the US Constitution guarantees that

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

(U.S. Const. amend. IV.) The problem exists because the Constitution fails to address the issue of technological advancement, let alone the issue of big data. The reason for such an “oversight” is simple: The founders could never have imagined technology so invasive as the cellular phone. Moreover, the language in the Fourth Amendment has never been updated since its inception over 200 years ago, which necessarily means that it is left up to the Supreme Court’s wisdom to apply the 200-year-old language to 21st-century problems.

Perhaps the largest contributor in the acquisition of big data is the cellular phone industry. There are 396 million cell phone service accounts, despite the United States having a population of only 326 million. (Carpenter v. United States, 138 S. Ct. 2206, 2211 (2018).) This means that there are about 1.215 cell phones for every one person—whether that person is an adult or a child—in the United States. Having a cell phone is no longer a luxury; rather, it is a necessity if one wishes to partake in American society. However, this necessity comes with some consequences. One of the most notable is that the cell phone service provider (CPSP)—whether that be Verizon, Sprint, T-Mobile, etc.—has a database that functionally details our lives. This means that the CPSP can use all these data points generated from the cell phone to put together a picture of our entire lives: how old we are, our sexual orientation, our religious beliefs, and our political affiliation, along with any other intimate details. This is done through the acquisition of cell-site location information (CSLI).

CSLI is gathered through a complex mathematical algorithm; however, a working knowledge of the mathematics is not necessary. An article published in the John Marshall Journal of Information Technology and Privacy Law did a great job of simplifying the mechanics:

Unlike traditional land-based lines, cell phones rely on radio waves in order to communicate between the handset and the cellular service network of radio based stations called “cell sites,” which are distributed throughout various geographic coverage areas. The quality of the signals to and from the cell sites is typically measured by what most cell phones users understand as the “bars.” Whether or not a user is actively engaged in a call, the cell-phone will constantly remain in contact with nearby cell towers. The quality and strength of the signals determine through which towers calls are routed both to and from the cell phone in order to provide for best possible reception and least cross-interference with other cell users.

(Lance H. Selva et al., Rise of the Mosaic Theory: Implications for Cell Site Location Tracking by Law Enforcement, 32 J. Marshall J. Info. Tech. & Privacy L. 235, 238 (2016).) As time goes on, CPSPs open new accounts with more customers, which results in an increase in the number of cell towers. This necessarily creates substantially more accurate location data on a person because “if at least three towers that are receiving signals are used in the triangulation process, a nearly precise location of the phone may be determined, perhaps even to a particular floor or room within a building.” (Id. at 239.)

However, consumers are not the only ones who “benefit” from advancing technology. As technology advances, so do police investigative techniques. One recent development in police investigative tactics is the use of cell-site simulators (CSS), sometimes referred to as “IMSI catcher,” “stingray,” “triggerfish,” or “swamp box.” What a CSS does is it mimics the signal of a cell phone tower, causing cell phones to contact the CSS, thus providing information such as the location of the cell phone with a margin of error of only a few feet. The functional result is that police officers can track an individual’s movements within her home, without actually entering the dwelling, a historically constitutionally protected area. It is this obscene behavior that gives rise to the constitutional issue posed by CSLI.

The Fourth Amendment Protects People, Not Places

Nearly 100 years ago in Olmstead v. United States, the Supreme Court set forth the rule that for a search to be considered a search for Fourth Amendment purposes, there must be an actual, physical trespass of the individual’s person, house, papers, or effects. (277 U.S. 438 (1928).) The Court ruled that because the tapping of the plaintiff’s phone did not require a physical intrusion, there was no search under the Fourth Amendment, and therefore no warrant was needed. (Id.) The Court notes that “the well known historical purpose of the Fourth Amendment, directed against general warrants and writs of assistance, was to prevent the use of governmental force to search a man’s house, his person, his papers and his effects; and to prevent their seizure against his will.” (Id. at 463.) The Court also notes that “the Amendment itself shows that the search is to be of material things—the person, the house, his papers or his effects. The description of the warrant necessary to make the proceeding lawful, is that it must specify the place to be searched and the person or things to be seized”; however, a few decades later, the Court deviated from the common law rule of trespass in favor of a different standard. (Id. at 464.)

In a nearly identical factual scenario, the Court found that the installation of a listening device to the telephone lines of a public phone both constituted a search under the Fourth Amendment, and therefore required a warrant. (Katz v. United States, 389 U.S. 347 (1967).) The Court made the decision to deviate from, but not abandon, the old common law rule that required a physical trespass in favor of a rule that was more suitable for the year 1967 and onwards. (See Alderman v. United States, 394 U.S. 165, 180 (1969) (“We do not believe that Katz, by holding that the Fourth amendment protects persons and their private conversations, was intended to withdraw any of the protection which the Amendment extends to the home . . .”).) The rule the Court adopted is perhaps most accurately captured in Justice Harlan’s concurring opinion. The rule requires “first that a person have exhibited an actual (subjective) expectation of privacy and, second, that the expectation be one that society is prepared to recognize as ‘reasonable.’” (Katz, 389 U.S. at 361 (Harlan, J., concurring).) It can be said that Justice Harlan, through the second element “that the expectation be one that society is prepared to recognize as ‘reasonable,’” viewed the Constitution to be a living document that should be interpreted and applied differently as modern society progresses. (Id. (emphasis added).) Put simply:

. . . the Fourth Amendment protects people, not places. What a person knowingly exposes to the public, even in his own home or office, is not subject of Fourth Amendment protection. See Lewis v. United States, 385 U.S. 206, 210; United States v. Lee, 274 U.S. 559, 563. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected. See Rios v. United States, 364 U.S. 253; Ex parte Jackson, 96 U.S. 727, 733.

(Katz, 389 U.S. at 352–53 (majority op.). Even in 1967 the Court understood that there is a need to distinguish that which is intended for public consumption and that which is not. Moreover, the Court knew that simply because someone is in a public atmosphere does not necessarily mean that she relinquishes all sense of privacy.

Third-Party Doctrine

An individual’s right to privacy took a major step backwards when the Court’s decision that established the Third-Party Doctrine was put in effect. In Smith v. Maryland, the Court was faced with a very important question: whether the use of a pen register by police violated an individual’s Fourth Amendment rights. (442 U.S. 735 (1979).) Upon police request and without a warrant, Smith’s telephone company installed a pen register, which effectively kept an active log of all numbers dialed for outgoing calls. (Id. at 737.) This was ruled to be a legal act that did not violate the Fourth Amendment’s requirement of a warrant based on probable cause. The Court noted that pen registers are commonly used “for the purposes of checking billing operations, detecting fraud, and preventing violations of law.” (Id. at 742 (quoting United States v. New York Tel. Co., 434 U.S. 159, 174–75 (1977)).) Because pen registers are commonly used, all phone users realize that they must convey phone numbers to the telephone company when making calls, and because all users realize that the phone company has “facilities” for keeping a record of the long-distance phone calls, due to their monthly phone bills, the users could not have exhibited an actual, subjective, expectation of privacy. (Id. at 742.) Thus, the Third-Party Doctrine effectively says, “a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.” (Id. at 743–44.)

The rule established in Smith, while unknown to the majority at the time, created substantial dangers to consumers in the Information Age some 30 years later. In modern society, consumers voluntarily convey virtually all of their information to third parties. Whenever one purchases a new phone, one must agree to the terms and conditions before even gaining access to the phone itself. One of the typical terms to which we must agree is to allow the developer, and in effect our CPSP, to have access to our location information. This information, among other uses, is used to target our devices for specific advertisements. It works similarly to Google’s ad targeting technique, which is why one sees ads on websites such as Facebook for products that one has recently googled. Under the rule established in Smith, all of the location information voluntarily conveyed to the CPSP would not be subject to Fourth Amendment protection, and thus would be subject to seizure by law enforcement without a warrant.

How the Court Has Addressed Location Tracking Technology

Since the decision in Smith, the Court has addressed the issue of location tracking by police with the use of technology. In United States v. Knotts, the Court addressed the issue of location tracking through the use of a beeper. (460 U.S. 276 (1983).) The police suspected a group of men to be making and selling narcotics. (Id. at 278.) The police, with the permission of a chemical company’s officers, installed a beeper in a drum of chloroform that was to be given to the defendants later that day. (Id.) When the defendants picked up the drum with the beeper in it, the police proceeded to follow the car in which the chloroform was placed. (Id.) During the “latter part of the journey,” the law enforcement officers, at approximately the same time, lost visual sight of the car and the beeper signal. (Id.) Using a monitoring device on a helicopter, the police were able to locate the beeper signal approximately an hour later, only this time the signal was stationary at a cabin occupied by one of the defendants. (Id.) The Court ruled that there was no reasonable expectation of privacy because the defendants were traveling on public roads. The Court noted that

[a] person traveling on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another. When [respondent] traveled over the public streets he voluntarily conveyed to anyone who wanted to look the fact that he was traveling over particular roads in a particular direction, the fact of whatever stops he made, and the fact of his final destination when he exited from public roads onto private property.

(Id. at 281–82.) The respondent argued that the result of allowing this type of behavior would result in allowing “twenty-four hour surveillance of any citizen of this country” without a warrant. (Id. at 283.) The Court rejected this argument noting that “if such dragnet-type law enforcement practices as respondent envisions should eventually occur, there will be time enough then to determine whether different constitutional principles may be applicable.” (Id. at 284.)

In United States v. Jones, the Court addressed the issue of whether the placement of a global positioning system (GPS) on the defendant’s Jeep without a valid warrant constituted an illegal search in violation of the Fourth Amendment. (565 U.S. 400 (2012).) The defendant Jones was suspected of trafficking illegal narcotics into the District of Columbia (DC). Law enforcement was granted a warrant for the installation of a GPS tracking device on the defendant’s Jeep within DC and within 10 days. (Id. at 402–403.) However, the device was not installed until the 11th day after the warrant was issued, and the device itself was installed in Maryland rather than in DC. (Id. at 403.) The GPS tracked the defendant for the next 28 days. (Id.) While the majority’s opinion is based on the old rule of trespass, arguing that the Jeep constituted “an effect” of Jones, the concurring opinions are more applicable to the topic of this article. (Id. at 404.) One of the concurring opinions even foresaw the issue at hand by noting that “with increasing regularity, the government will be capable of duplicating the monitoring undertaken in this case by enlisting factory- or owner-installed vehicle tracking devices or GPS-enabled smartphones.” (Id. at 415 (Sotomayor, J., concurring).) Justice Sotomayor saw that “GPS-enabled smartphones” required the need to reevaluate the Third-Party Doctrine, foreshadowed nearly 30 years prior by the majority in Knotts and discussed in the following case. (Id.)

Recently, the Court released an opinion that is, in essence, a culmination of Smith, Knotts, and Jones. In Carpenter v. United States, the Court addressed the constitutionality of a magisterial order to a CPSP mandating the production of archived GPS location information absent a valid warrant. (138 S. Ct. 2206 (2018).) In 2011 law enforcement agents arrested four men in connection with a series of robberies. (Id. at 2212.) During interrogations, one of the four men gave up an additional 15 accomplices and provided their cell phone numbers. (Id.) After reviewing the man’s cell phone records, the officers applied for a court order pursuant to the Stored Communications Act, which instructed the defendant’s CPSPs to produce “cell/site sector [information] for [Carpenter’s] telephone[] at call origination and call termination for incoming and outgoing calls” for the four months during which the robberies took place. (Id.) Using this information, “Carpenter was charged with six counts of robbery and an additional six counts carrying a firearm during a federal crime of violence.” (Id.) The Court declined to extend the Third-Party Doctrine of Smith to circumstances of this nature, and instead found that “whether the Government employs its own surveillance technology as in Jones or leverages the technology of a wireless carrier, we hold that an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through CSLI.” (Id. at 2217.) This ruling logically followed from the six-year-old decision in Jones.

In a concurring opinion authored by Justice Sotomayor, she states that

[m]ore fundamentally, it may be necessary to reconsider the premise that an individual has no reasonable expectation of privacy in information voluntarily disclosed to third parties. This approach is ill suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks.

(United States v. Jones, 565 U.S. 400, 417 (2012) (Sotomayor, J., concurring) (citations omitted).) This is precisely what the majority in Carpenter decided to do. The type of monitoring that occurred in Carpenter was exactly the “dragnet-type law enforcement practices” to which the majority in Knotts was referring. (United States v. Knotts, 460 U.S. 276, 284 (1983).) After all, “GPS monitoring generates a precise, comprehensive record of a person’s public movements that reflects a wealth of detail about her familial, political, professional, religious, and sexual associations.” (Jones, 565 U.S. at 415 (Sotomayor, J., concurring).) If that sentence alone from Justice Sotomayor’s concurring opinion was not enough to persuade the Court to find that people maintained a reasonable expectation of privacy in CSLI, the circumstances in Carpenter go one step further than the GPS tracker in Jones; a person’s cell phone goes with her everywhere. As Chief Justice Roberts accurately stated, “while individuals regularly leave their vehicles, they compulsively carry cell phones with them all the time.” (Carpenter, 138 S. Ct. at 2218.) This ultimately means that at some point, CSLI data will be tracking the individual within the privacy of her own home.

What Does This Mean for the Use of CSS?

A case that would arise through the use of CSS by law enforcement agents would be functionally no different than what happened in Carpenter, such as what would arise from police officers sitting outside the suspect’s house with a CSS device. The only real difference is that instead of a court mandating that the CPSP produce the CSLI-gathered information, the police are unilaterally using the same exact method of pinpointing a suspect’s location with a margin of error of only a few feet. It is a long-standing rule that what an individual does within the confines of her own home outside the view of the public is constitutionally protected by the Fourth Amendment. (See Weeks v. United States, 232 U.S. 383 (1914) (Court ruled that the entry by police using a spare key and the ensuing seizure of papers from defendant’s room constituted an illegal search); Kyllo v. United States, 533 U.S. 27 (2001) (Court found that the use of a thermal imaging device to detect high amounts of heat within a garage constituted a search requiring a warrant); Florida v. Jardines, 569 U.S. 1 (2013) (Court found that the use of a trained K-9 unit to sniff out narcotics on defendant’s porch constituted an illegal search).) Applying the ruling in these cases in conjunction with the ruling in the cases discussed above to the issue of CSS when employed by law enforcement agents becomes a lot clearer.

The CSS not only tracks the suspects while they are on the roads, but because the CSS tracks cell phones, it necessarily tracks the suspects within the confinements of private property. The use of CSS on individuals within their own homes without a warrant would be found to constitute an illegal search in violation of the Fourth Amendment, simply by applying the precedents of Weeks, Kyllo, and Jardines. However, the issue using the CSS to track the location of suspects outside the home is a little less clear.

A hypothetical case that would arise through the use of CSS would be very similar to Smith, Knotts, Jones, and Carpenter. It would be similar to Smith because all of the location information that the CSS would be gathering is voluntarily conveyed to the CPSP. It would be similar to Knotts because it would involve tracking a suspect on public roadways. It would be similar to Jones and Carpenter because it would revolve around the acquisition of location information through the use of technology. However, upon further examination, one can rule out Smith because, as Chief Justice Roberts said in Carpenter, “given the unique nature of cell-site records, this Court declines to extend Smith and Miller to cover them.” (Carpenter, 138 S. Ct. at 2209.) This conclusion necessarily disregards Knotts because the potential for mass surveillance without a warrant is exactly the type of “dragnet-type law enforcement practices” that the majority in Knotts discussed. (Knotts, 460 U.S. at 284.) By process of elimination, the only two cases left to be discussed are Jones and Carpenter.

In the majority opinion of Jones, Justice Scalia noted that to constantly tail a vehicle for four weeks “would have required a large team of agents, multiple vehicles, and perhaps aerial assistance” and that “only an investigation of unusual importance could have justified such an expenditure of law enforcement resources.” (Jones, 565 U.S. at 429.) This implies that if the GPS tracker was hypothetically used to track only one trip, then that might have been acceptable; however, the concurring justices disagree. Justice Sotomayor was able to see the bigger picture and apply a different reasoning. As stated in Carpenter, “as with GPS information, the time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his ‘familial, political, professional, religious, and sexual associations.’” (Carpenter, 138 S. Ct. at 2217 (Sotomayor, J., concurring).) While it does not explicitly overrule Jones, it implicitly creates serious questions about the weight of the majority’s decision in Jones, as applied to these circumstances. It does this because functionally, the data acquired through the use of the GPS tracking device in Jones are not all that different from the CSLI gathered in Carpenter. Therefore, Carpenter should be what is used as a precedent to determine whether the use of CSS by law enforcement would constitute a search under the Fourth Amendment, therefore requiring a warrant.

Conclusion

If this article would have been written prior to June 2018, it would have come to the conclusion that the Third-Party Doctrine needed to either be changed or have limitations placed on it to suit the technology of the Digital Age. However, Carpenter correctly addresses the issue of the Third-Party Doctrine by declining to extend its application to CSLI. The relevance of the precision of the CSS poses a problem because it effectively allows the police to search one’s home without ever entering the building. This threat should be quelled through the discussion of Weeks, Kyllo, and Jardines. Therefore, the use of CSS to track someone within his or her home without a warrant is a violation of the Fourth Amendment. Finally, the length of time that the CSS is being used is relevant.

As discussed in the majority opinion in Jones, it would have been nearly impossible for law enforcement to track a vehicle nonstop for four weeks. And similarly, in Knotts, the beeper’s signal was only tracked for one trip—from the store to the cabin. This means that there is a point at which location tracking through the use of technology becomes unconstitutional, and that point is after one trip, but most certainly before four weeks. Given how precise CSS are, it is very likely that there could be sufficient information to reach the “dragnet-type” tactics after one day of surveillance, especially if the suspect makes multiple trips. (Knotts, 460 U.S. at 284.) It is also important to note that the only way for anyone to avoid such surveillance is to “forgo use of what for many has become a personal or professional necessity.” (Smith v. Maryland, 442 U.S. 735, 750 (1979) (Marshall, J., dissenting). Bear in mind that was stated in 1979, when the thought of carrying in one’s pocket a computer that can make phone calls, receive text messages, and access the Internet was more science fiction than a future reality.

In modern society, in the Digital Age, it is impossible to function without a cell phone. In essence, one must ultimately choose to be a functioning member of society but be subject to constant surveillance, or to lack the ability to function but be shielded from constant surveillance. For the foregoing reasons, the use of CSS by law enforcement agents without a warrant ought to be ruled an unconstitutional search in violation of the Fourth Amendment.