In re Application for Tel. Info. Needed for a Criminal Investigation

• Decision Date: 29 July 2015
• Docket Number: Case No. 15–XR–90304–HRL–1(LHK)
• Citation: 119 F.Supp.3d 1011
• Parties: In re: Application for Telephone Information Needed for a Criminal Investigation
• Court: U.S. District Court — Northern District of California

119 F.Supp.3d 1011

In re: Application for Telephone Information Needed for a Criminal Investigation

Case No. 15–XR–90304–HRL–1(LHK)

United States District Court, N.D. California, San Jose Division.

Signed July 29, 2015

ORDER AFFIRMING DENIAL OF APPLICATION FOR HISTORICAL CELL SITE LOCATION INFORMATION

[PUBLIC REDACTED VERSION]

LUCY H. KOH, United States District Judge

Before the Court is the government's appeal of U.S. Magistrate Judge Howard R. Lloyd's denial of an application for an order pursuant to 18 U.S.C. § 2703(d) authorizing the government to obtain historical cell site location information ("CSLI") associated with [Redacted] target cell phones.ECF No. 4("Gov't Br.");ECF No. 5("Gov't Supp. Br.").¹The Federal Public Defender for the Northern District of California("Public Defender"), at the Court's invitation, filed a response.ECF No. 21("Opp.").With the Court's permission, the American Civil Liberties Union ("ACLU") and the Electronic Frontier Foundation ("EFF") filed amicus briefs in support of the Public Defender.ECF No. 19("ACLU Br.");ECF No. 20("EFF Br.").The government replied.ECF No. 22("Gov't Reply").Having considered these written submissions, the relevant law, the record in this case, and the oral arguments presented at the June 24, 2015 hearing, the Court hereby AFFIRMS Judge Lloyd's denial of the government's application for historical CSLI.

I.BACKGROUND

A.Cell Phone Technology and CSLI

Cell phones operate through the use of radio waves.To facilitate cell phone use, cellular service providers maintain a network of radio base stations—also known as cell towers—throughout their coverage areas.See Electronic Communications Privacy Act (ECPA)(Part II): Geolocation Privacy and Surveillance, Hearing Before the Subcomm. on Crime, Terrorism, Homeland Security, and Investigations, of the H. Comm. on the Judiciary,113th Cong. 50(2013)(written testimony of Prof. Matt Blaze, University of Pennsylvania)("Blaze Testimony"), available at http://www.judiciary.house.gov/index.cfm?a=Files.Serve & File_id=91FBF844–052E–4743–9CCE–19168FA815D2.Most cell towers have multiple cell sectors (or "cell sites") facing in different directions.ECFNo. 22–1, Declaration of Special Agent Hector M. Luna ("Luna Decl.")¶ 3A.A cell site, in turn, is a specific portion of the cell tower containing a wireless antenna, which detects the radio signal emanating from a cell phone and connects the cell phone to the local cellular network or Internet.Blaze Testimonyat 50.For instance, if a cell tower has three antennas, each corresponding cell site would service an area within a 120–degree arc.SeeThomas A. O'Malley, Using Historical Cell Site Analysis Evidence in Criminal Trials, U.S. Att'y Bull., Nov. 2011, at 19, available at http://www.justice.gov/usao/eousa/foia_reading_room/usab5906.pdf.

Whenever a cell phone makes or receives a call, sends or receives a text message, or otherwise sends or receives data, the phone connects via radio waves to an antenna on the closest cell tower, generating CSLI.The resulting CSLI includes the precise location of the cell tower and cell site serving the subject cell phone during each voice call, text message, or data connection.Luna¶ 3A.If a cell phone moves away from the cell tower with which it started a call and closer to another cell tower, the phone connects seamlessly to that next tower.Blaze Testimonyat 50.

Significantly, the government's special agent from the Federal Bureau of Investigation ("FBI") informs the Court that CSLI may be generated in the absence of user interaction with the cell phone.LunaDecl. ¶ 3B.For example, CSLI may still be generated during an incoming phone call that is not answered.Id.Additionally, most modern smartphones have applications that continually run in the background, sending and receiving data without a user having to interact with the cell phone.Id.

Indeed, cell phones, when turned on and not in airplane mode, are always scanning their network's cellular environment.LunaDecl. ¶ 3B.In so doing, cell phones periodically identify themselves to the closest cell tower—i.e., the one with the strongest radio signal—as they move throughout their network's coverage area.Blaze Testimonyat 50.This process, known as "registration" or "pinging," facilitates the making and receiving of calls, the sending and receiving of text messages, and the sending and receiving of cell phone data.Seeid.Pinging is automatic and occurs whenever the phone is on, without the user's input or control.U.S. Dep't of Homeland Sec., Lesson Plan: How Cell Phones Work 9 (2010)("DHS Lesson Plan"), available athttps://www.eff.org/files/filenode/3259_how_cell_phones_work_lp.pdf.A cell phone that is switched on will ping the nearest tower every seven to nine minutes.Id.At oral argument, the Court was informed that at least some cellular service providers keep track of the CSLI generated by registration "pings."Hr'gTr. at 4:19–5:6.

As the number of cell phones has increased, the number of cell towers—and thus cell sites—has increased accordingly:

A sector can handle only a limited number of simultaneous call connections given the amount of radio spectrum "bandwidth" allocated to the wireless carrier.As the density of cellular users grows in a given area, the only way for a carrier to accommodate more customers is to divide the coverage area into smaller and smaller sectors, each served by its own base station and antenna.New services, such as 3G and LTE/4G Internet create additional pressure on the available spectrum bandwidth, usually requiring, again, that the area covered by each sector be made smaller and smaller.

Blaze Testimonyat 54.Densely populated urban areas therefore have more cell towers covering smaller geographic locations.For example, the Public Defender informs the Court that within three miles of the San Jose Federal Courthouse, there are 199 towers (with applications for three more currently pending) and 652 separate antennas.Opp.at 3.Within just one mile of the Federal Courthouse in New York City, there are 118 towers and 1,086 antennas.Id.

In addition to the large, three-sided cell towers, smaller and smaller base stations are becoming increasingly common.Examples include microcells, picocells, and femtocells, all of which cover a very specific area, such as one floor of a building, the waiting room of an office, or a single home.Blaze Testimonyat 43–44.This proliferation of base stations to cover smaller areas means that "knowing the identity of the base station (or sector ID) that handled a call is tantamount to knowing a phone's location to within a relatively small geographic area ... sometimes effectively identifying individual floors and rooms within buildings."Id. at 55–56.Although the ability of cellular service providers to track a cell phone's location within an area covered by a particular cell site might vary, it has become ever more possible for the government to use CSLI to calculate a cell phone user's "locations with a precision that approaches that of GPS."Id. at 53.

The government acknowledged as much at oral argument, conceding that CSLI has gotten more precise over the years.Hr'gTr. at 32:5–9.The fact is new tools and techniques are continually being developed to track CSLI with greater precision.Cellular service providers, for instance, can triangulate the location of a cell phone within an area served by a particular cell site based on the strength, angle, and timing of that cell phone's signal measured across multiple cell site locations.Blaze Testimonyat 56.

Lastly, the volume of location data generated by an individuals' cell phone can be immense, as the ACLU points out.SeeACLU Br.at 5–7;ECFNo. 19–1, Declaration of Nathan Freed Wessler("Wessler Decl.").For example, in United States v. Carpenter,a case now pending in the Sixth Circuit and arising out of the greater Detroit area, the government obtained 127 days of CSLI for one defendant, Timothy Carpenter, and 88 days of CSLI for another, Timothy Sanders.SeeUnited States v. Carpenter,No. 14–1572(6th Cir. filed May 7, 2014).Carpenter's data include 6,449 separate call records for which CSLI was logged, comprising 12,898 cell site location data points.SeeWesslerDecl. ¶ 8.Sanders's records reveal 11,517 calls for which location information was logged, comprising 23,034 cell site location data points.Id.¶ 9.Carpenter and Sanders, respectively, placed or received an average of 50.8 and 130.9 calls per day for which location data was recorded and later obtained by the government.Id.¶ 10.For Carpenter, that amounts to an average of 102 location points per day, or one location point every 14 minutes.For Sanders, it amounts to an average of 262 location points per day, or one location point every six minutes.

B.Statutory Framework

An application for historical CSLI is governed by the Stored Communications Act ("SCA"), 18 U.S.C. § 2701 et seq., which was enacted in 1986 as Title II of the Electronic Communications Privacy Act("ECPA").The SCA covers the disclosure of communication information by providers of electronic communications, including cellular service providers.Section 2703(a) covers circumstances in which a government entity may require such providers to disclose the contents of wire or electronic communications in electronic storage, while § 2703(b) covers circumstances in which a government entity may require providers to disclose the contents of wire or electronic communications held by a remote computing service.Seeid.§ 2703(a)-(b).Neither of these provisions is at issue here.

Instead, the government seeks what is referred to in § 2703(c) as "a record or other information pertaining to a subscriber to or customer of [a provider of electronic communication service]," a term that expressly excludes the contents of communications.18 U.S.C. § 2703(c)(1).Although the SCA makes no mention of historical...