United States District Court Northern District of California Case5:15-xr-90304-HRL Document30 Filed07/29/15 Page42 of 46 1 procedures described in the Federal Rules of Criminal Procedure” in order to acquire “a record or 2 other information pertaining to a subscriber to or customer of [a provider of electronic 3 communication service].” 18 U.S.C. § 2703(c)(1)(A). Further, although requiring a warrant for 4 historical CSLI will surely have an impact on law enforcement practices, this requirement “is ‘an 5 important working part of our machinery of government,’ not merely ‘an inconvenience to be 6 somehow weighed against the claims of police efficiency.’” Riley, 134 S. Ct. at 2493 (quoting 7 Coolidge v. New Hampshire, 403 U.S. 443, 481 (1971)). It may be true that court orders for 8 historical CSLI have served as “an investigative tool” used to establish probable cause in the past, 9 Gov’t Reply at 11, but the government is “not free from the warrant requirement merely because it 10 is investigating criminal activity,” Third Circuit Opinion, 620 F.3d at 318. “Recent technological 11 advances,” moreover, “have . . . made the process of obtaining a warrant itself more efficient.” 12 Riley, 134 S. Ct. at 2493; see also Missouri v. McNeely, 133 S. Ct. 1552, 1573 (2013) (Roberts, 13 C.J., concurring in part and dissenting in part) (explaining that in some jurisdictions “police 14 officers can e-mail warrant requests to judges’ iPads; judges have signed such warrants and e- 15 mailed them back to officers in less than 15 minutes”). 16 Finally, the Court does not hold that the government may never obtain historical CSLI 17 without a warrant supported by probable cause. It may be that “other case-specific exceptions,” 18 such as exigent circumstances, would “still justify a warrantless search” for historical CSLI. 19 Riley, 134 S. Ct. at 2494. It may also be that historical CSLI acquired without a warrant is 20 admissible at trial under the exclusionary rule’s good faith exception. In general, however, if the 21 government wants to obtain historical CSLI associated with a particular cell phone, the Fourth 22 Amendment requires that the government secure a warrant before doing so. 23 24 D. Remedy Having found that the Fourth Amendment generally requires that the government obtain a 25 warrant supported by probable cause before acquiring a cell phone user’s historical CSLI from a 26 cellular service provider, the Court must address whether such a conclusion renders any part of the 27 28 42 Case No. 15-XR-90304-HRL-1(LHK) ORDER AFFIRMING DENIAL OF APPLICATION FOR HISTORICAL CELL SITE LOCATION INFORMATION