On May 16, 2017, the United States District Court for the Northern District of Illinois, in United States v. Rosario, 2017 WL 2117534 (N.D. ILL. May 16, 2017), held that the Government’s acquisition of cell-site location information (CSLI) from a third-party provider did not constitute a search in violation of the Fourth Amendment.


On or around December 5, 2016, a store in Ann Arbor, Michigan that specialized in the sale of firearms, rare coins, and precious metals was burglarized after it closed for the day.  According to the store’s owner, about forty-five minutes prior to closing for the day on December 5th, three men entered the store to look at firearms.  When the owner returned to the store the next day, he discovered that the store was burglarized. The owner also determined that, after the store had closed for the day on December 5th, it had received a phone call from a private caller.  The owner passed this information on to law enforcement, who in turn contacted Comcast, the store’s telephone provider, to request the private caller’s phone number.  Comcast complied with this request and provided the number to the officers.

Subsequently, the officers determined that Sprint was the service provider for the cell phone number that Comcast had provided. The officers contacted Sprint to request CSLI for the cell phone and Sprint provided this information.  The CSLI revealed that the phone had pinged off a tower in Ann Arbor, Michigan, on the evening of December 5th. After obtaining the CSLI, officers then found out that the phone number had been provided to a Comfort Inn under a person called Joel Rosario.

Ultimately, in February 2016, Defendant Rosario was charged with interstate transportation of stolen property and possession of firearm in violation of federal law. During discovery, the prosecution disclosed the CSLI to Rosario’s attorney.  Rosario filed a motion to suppress the CSLI. Rosario argued that the acquisition of CSLI from his provider violated his Fourth Amendment rights because the officers acquired it without first obtaining a warrant.


In determining whether the Government’s acquisition of CSLI from a third-party service provider violates a reasonable expectation of privacy so as to constitute a search under the Fourth Amendment, the District Court noted that every federal court of appeals that had confronted the issue held that the acquisition of CSLI from a third-party service provider was not a Fourth Amendment search. In holding that the acquisition of CSLI from a service provider does not require a warrant, the District Court relied on the third-party doctrine.

Under the third-party doctrine, an individual does not have a reasonable expectation of privacy in information he or she voluntary turns over to a third-party, and the Government therefore does not engage in a Fourth Amendment search when it acquires that information.  Smith v. Maryland, 442 U.S. 735 (1979). The rationale is that an individual takes the risk, in revealing his or her affairs to another, that the information will be conveyed by that person to the Government.  The third-party rule applies to information provided to a third-party even if the information is revealed on the assumption that it will be used only for a limited purpose and the confidence placed in the third-party will not be betrayed.

The District Court based its decision on a United States Supreme Court case entitled Smith v. Maryland.  In that case, the Court had to determine whether the Government’s use of a pen register to record the numbers dialed on a home telephone constituted a search under the Fourth Amendment. The Court applied the third-party doctrine and held that use of such a pen register did not constitute a Fourth Amendment search.  The Court reasoned that when the petitioner used his phone, he voluntarily conveyed numerical information [i.e. the phone numbers he dialed] to the phone company and exposed the information to its equipment in the ordinary course of business, which, in turn, could not create an expectation of privacy in the numbers he dialed.

With Smith in mind, the District Court in Rosario ruled that a cell phone user voluntarily conveys CSLI to his third-party service provider when he operates his cell phone.  Accordingly, he cannot claim a legitimate expectation of privacy or that the Government’s acquisition of CSLI is a Fourth Amendment search.

The District Court reasoned that its common sense that all telephone users realize that they must convey phone numbers to the telephone company and that the phone company has facilities for making permanent records of the numbers they dial.  Additionally, the District Court noted that cell phone users should be aware that a cell phone must send and receive wireless signals to and from a nearby tower to transmit phone calls and text messages therefore when a person purchases a cell phone and chooses a service provider, he should expect the provider will route outgoing and incoming calls and text messages. Lastly, the District Court indicated that purchasing a phone, selecting a service provider, turning on the phone, making a phone call or sending a text message involved voluntary acts at every step.

Ultimately, the District Court denied Defendant Rosario’s motion to suppress the CSLI evidence. The District Court determined that Rosario voluntarily conveyed his CSLI to Sprint when he operated his cell phone.  As such, Rosario did not have a reasonable expectation of privacy in Sprint’s records of CSLI and the Government’s acquisition of the CSLI from Sprint did not constitute a search under the Fourth Amendment.


Although this is a District Court case, and not binding on jurisdictions in California, the Rosario decision is an indicator of how District Courts in the Ninth Circuit may rule when presented with the same issue.  In a California District Court case from 2015, entitled United States v. Dorsey, 2015 U.S. Dist. LEXIS 23693 (Cal. 2015), the Court ruled that an order for similar cell phone location information obtained pursuant to 18 U.S.C. § 2703(d), part of the federal Stored Communications Act (“SCA”), did not implicate the Fourth Amendment. The Dorsey Court noted that other courts determining the issue had similarly ruled that there was no reasonable expectation of privacy under the Fourth Amendment for CLSI.  Id. at *19 – *26.  Based upon these holdings, if your agency decides to use CSLI in support of criminal cases, the third-party doctrine may be raised as a defense to a motion to suppress evidence if the defendant claims a Fourth Amendment violation arising from use of CSLI.  As usual, you should obtain your legal counsel’s advice on such matters prior to determining a course of action in any particular case.

As always, if you wish to discuss this matter in greater detail, please feel free to contact me at (714) 446 – 1400 or via email at jrt@jones-mayer.com.

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