Is the Reverse Location Search Warrant Heading in the Wrong Direction?

Prior to the first phase of reverse locational search technology, law enforcement officials had to physically search within a vicinity and interview people to find leads—including the identities of persons who may have been near the scene of the criminal activity under investigation. In addition to what may be considered more conventional policework, law enforcement can now analyze cell phone users’ proximity based on cell phone usage.

The Stored Communications Act (SCA) controls the disclosure of electronic communications and transactional records maintained by third-party internet service providers and wireless carriers. (See 18 U.S.C.A. § 2701 et seq.) The SCA contains certain procedural safeguards with respect to notifying subscribers or customers of a wireless carrier and/or remote computing service. Section 2703(b)(A) does not require notice to the customer if the government obtains a search warrant; however, section 2703(b)(B) provides for notice to the subscriber or customer if the government issues an administrative subpoena to the carrier and/or provider or obtains a court order under section 2703(d). (See 18 U.S.C.A. § 2703(d).) Section 2703(d) states, in part, that a court of competent jurisdiction shall issue an order for information covered by the SCA provided “specific and articulable facts” showing a relevant and material connection between information sought and an ongoing criminal investigation are explained in the government’s application.

The prolific nature of internet access in varying settings creates a relatively broad spectrum of what society would likely consider to be “private.” In addition to the geographical movements of the cell phone user, the reverse location search warrant could return information about through which IP access point the data were transmitted, such as payment terminals and WiFi routers. If one happens to use Google Pay to make a purchase at a convenience store within the coordinates of the warrant, that person may be subject to a search despite having no association with the activity under investigation. Alternatively, if one is driving through the geographical vicinity covered by the warrant, the privacy interest in that person’s phone activity may be compromised simply because the individual happened to be using Google Maps.

In Carpenter v. United States, 138 S. Ct. 2206 (2018), the United States Supreme Court held that the warrant requirement of the Fourth Amendment now applies to cell-site location information (CSLI). Six years earlier, in United States v. Jones, 565 U.S. 400 (2012), the Supreme Court held that the warrantless installation of a GPS tracking device on a suspect’s vehicle constituted an unlawful search under the Fourth Amendment. Therefore, the law as it currently stands in the United States is that whether gathering locational information on an individual through one’s cell phone and/or vehicle, government officials must secure a warrant to track a person’s whereabouts without consent. But what about the privacy rights of persons who are unknown to law enforcement and happen to be in the vicinity of the activity under investigation by coincidence? With the advent of reverse location search warrants, the answer to this question is not necessarily straightforward.

Carpenter extends the probable cause requirement for a search warrant to access historical CSLI—but the context of the analysis concerned an individual the government had identified. (See Carpenter, 138 S. Ct. 2206.) Carpenter reiterates an extremely important principle about the historical intent of the Fourth Amendment:

We have kept this attention to Founding-era understandings in mind when applying the Fourth Amendment to innovations in surveillance tools. As technology has enhanced the Government’s capacity to encroach upon areas normally guarded from inquisitive eyes, this Court has sought to “assure [ ] preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted.

(See id. at 2214 (citing Kyllo v. United States, 533 U.S. 27, 34 (2001)) (parallel citations omitted).)

A search warrant application rests on “probable cause,” which, as the Supreme Court has repeatedly explained, is a “non-technical standard” intended to be “practical.” (See Maryland v. Pringle, 540 U.S. 366, 370 (2003) (citing Illinois v. Gates, 462 U.S. 213, 231 (1983)) (parallel citations omitted).) The doctrine is derived, in the most part, from “. . . the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act. . . .” (See id.) The “. . . substance of all the definitions of probable cause is a reasonable ground for belief of guilt.” (See Brinegar v. United States, 338 U.S. 160, 175 (1949) (parallel citations omitted).) Unlike the kind of search warrant now required by Carpenter, a reverse location search warrant—in substantial part—is intended to narrow the pool of potential targets of a criminal investigation by identifying who was present in the vicinity. A warrant wherein the identity of the suspect is known to the government is not the same as a warrant intended to sweep for identities of cell phone users, most of whom are likely in the geographical radius of the warrant by happenstance. They are not entirely reciprocal applications of probable cause because the latter lacks the specificity contemplated by the Fourth Amendment. (See Groh v. Ramirez, 540 U.S. 551, 557 (2004) (parallel citations omitted).)

Where one travels can divulge more intimate information about the person than simply the coordinates at which the cell phone activity occurred. Identity is integral to establishing probable cause, and, therefore, there are numerous privacy risks posed by reverse location searches from which Carpenter and Jones may not sufficiently protect society. Not only does it lack specificity of the places to be searched and person(s) or item(s) to be seized, but a reverse location search warrant could also result in the government intruding in the private lives of unidentified individuals by analyzing from where they transmitted data—even if the individual subject to the reverse search has no relationship to the activity under investigation.

Information about an individual’s visit to a certain doctor’s office could be produced to the government simply because the phone transmitted data through an internet access point offered over WiFi to patients by the medical practice. Records produced could reveal information from which one’s religious practices can be inferred because the data subject to the warrant were sourced from an access point housed in a place of worship. Depending on the context, there is the risk of intrusion by the government’s analysis of one’s spending habits and the businesses a person may frequent due to the nature of the services and/or products offered. Similar to an intrusion on one’s right to private medical treatment, a reverse location search could infringe on an individual’s right not to be tracked inside his or her attorney’s office.

Citing the dissent in Olmstead v. United States, the Court in Carpenter acknowledged the emphasis Justice Brandeis placed on the Court’s obligation to safeguard the privacy rights of individuals so that the “progress of science” does not erode Fourth Amendment protections. (See Olmstead v. United States, 277 U.S. 438, 473–474 (1928), overruled in part by Katz v. United States, 389 U.S. 347 (1967) (parallel citations omitted).) There is a potential for law enforcement to embark on a geolocational fishing expedition without the requisite specificity upon which the Warrant Clause of the Fourth Amendment was founded.

Although a second search warrant is required to access more detailed individual user information following the first warrant for a reverse location search, the very nature of the initial first step of casting a wide net for subscriber data could arguably require a “next generation” analysis of probable cause, but with a heightened level of scrutiny. It may be time for the law to become more “technical” by applying stricter scrutiny to the traditional probable cause standard—especially when private details about an individual’s cell phone usage could ultimately be searched simply because the individual happened to be in the vicinity of a place at a certain time, and nothing more.