United States v. Sanchez-Jara

• Citation: 889 F.3d 418
• Decision Date: 03 May 2018
• Docket Number: No. 17-2593,17-2593
• Parties: UNITED STATES of America, Plaintiff-Appellee, v. Juan Manuel SANCHEZ-JARA, Defendant-Appellant.
• Court: United States Courts of Appeals. United States Court of Appeals (7th Circuit)

889 F.3d 418

UNITED STATES of America, Plaintiff-Appellee,

v.Juan Manuel SANCHEZ-JARA, Defendant-Appellant.

No. 17-2593

United States Court of Appeals, Seventh Circuit.

Argued April 6, 2018

Decided May 3, 2018

Paul H. Tzur, Attorney, Office of the United States Attorney, Chicago, IL, for Plaintiff–Appellee.

John T. Kennedy, Attorney, Evanston, IL, for Defendant–Appellant.

Before Easterbrook, Ripple, and Hamilton, Circuit Judges.

Easterbrook, Circuit Judge.

Like United States v. Patrick, 842 F.3d 540 (7th Cir. 2016), this appeal concerns the use of a cell-site simulator to locate someone. And like Patrick it does not require us to determine when, if ever, the use of this device must be authorized by a warrant supported by probable cause, for in this case such a warrant was obtained.

The warrant, issued by a federal district judge in July 2015, authorizes federal agents to use pen registers, trap-and-trace devices, historical cell-call records, and "electronic investigative techniques ... to capture and analyze signals emitted by the Subject Phones, including in response to signals sent by law enforcement officers" (boldface in original) to find two cell phones and understand the nature of their owners' apparently criminal activity. The warrant's reference to "electronic investigative techniques" is a description of a cell-site simulator, a device that pretends to be a cell tower and harvests identifying information, including location data, about every phone that responds to its signals. The Department of Justice contends that it discards information about all phones other than those it has been programmed to look for and does not obtain the contents of any call. Here is the Department's description:

Cell-site simulators ... function by transmitting as a cell tower. In response to the signals emitted by the simulator, cellular devices in the proximity of the device identify the simulator as the most attractive cell tower in the area and thus transmit signals to the simulator that identify the device in the same way that they would with a networked tower.

A cell-site simulator receives and uses an industry standard unique identifying number assigned by a device manufacturer or cellular network provider. When used to locate a known cellular device, a cell-site simulator initially receives the unique identifying number from multiple devices in the vicinity of the simulator. Once the cell-site simulator identifies the specific cellular device for which it is looking, it will obtain the signaling information relating only to that particular phone. When used to identify an unknown device, the cell-site simulator obtains signaling information from non-target devices in the target's vicinity for the limited purpose of distinguishing the target device.

By transmitting as a cell tower, cell-site simulators acquire the identifying information from cellular devices. This identifying information is limited, however. Cell-site simulators provide only the relative signal strength and general direction of a subject cellular telephone; they do not function as a GPS locator, as they do not obtain or download any location information from the device or its applications. Moreover, cell-site simulators used by the Department must be configured as pen registers, and may not be used to collect the contents of any communication, in accordance with 18 U.S.C. § 3127(3). This includes any data contained on the phone itself: the simulator does not remotely capture emails, texts, contact lists, images or any other data from the phone. In addition, Department cell-site simulators do not provide subscriber account information (for example, an account holder's name, address, or telephone number).

Department of Justice Policy Guidance: Use of Cell-Site Simulator Technology (Sept. 3, 2015) at 2. See also the Wikipedia entry at .

Whether the simulator works this way is potentially important, because the warrant did not authorize the investigators to obtain the contents of any calls, to plumb any phone's address book or instant messages, or otherwise to get anything except location and certain metadata, the sorts of things available from pen registers and trap-and-trace devices. To get the contents of calls and messages, the agents would have needed a warrant under the wiretap statutes. 18 U.S.C. §§ 2510 – 22. The agents did not obtain a warrant of that kind or satisfy the conditions, such as the attempted use of other investigatory means and the minimization of intrusion, that are essential to wiretap warrants.

The warrant issued in 2015 was based not on the wiretap statutes but on 18 U.S.C. § 2703(d) and Fed. R. Crim. P. 41. Subsection (d) provides that "reasonable grounds to believe that the contents of a wire or electronic communication, or the records or other information sought, are relevant and material to an ongoing criminal investigation" permit a judge to issue a warrant for the production of information described in ...