United States v. Timothy Carpenter, 926 F.3d 313

Timothy Carpenter was convicted of robbery and related gun charges after the government introduced 12,898 cell-site location information (CSLI) data points showing his phone’s movements during a series of robberies.
The FBI obtained Carpenter’s CSLI by seeking court orders under 18 U.S.C. § 2703(d) of the Stored Communications Act (SCA), not by obtaining a warrant. Two magistrate judges issued the § 2703(d) orders.
At trial the government used CSLI-based maps and call-detail records to place Carpenter near robbery locations; the district court denied a motion to suppress and a jury convicted.
The Sixth Circuit originally upheld the warrantless collection; the Supreme Court reversed in Carpenter v. United States, holding that CSLI is a Fourth Amendment search and generally requires a warrant.
On remand this panel considered whether the FBI agents acted in objectively reasonable good-faith reliance on § 2703(d), such that suppression would be unwarranted despite the Fourth Amendment violation.
The Sixth Circuit affirmed the denial of suppression, concluding the agents reasonably relied on the SCA (and existing precedent and magistrate orders) and therefore fall within the good-faith exception.

Issue	Carpenter's Argument	Government's Argument	Held
Whether the warrantless acquisition of CSLI violated the Fourth Amendment	CSLI reveals the whole of physical movements and is protected; warrant required	Acquisition via § 2703(d) is lawful without a warrant	Warrantless CSLI collection was a Fourth Amendment search; warrant required (per Supreme Court)
Whether the third-party doctrine permits warrantless CSLI collection	Third-party doctrine cannot defeat expectation of privacy in CSLI	CSLI obtained from carriers is third-party records and permissible under § 2703(d)	Third-party doctrine does not shield CSLI; users do not meaningfully assume surrender of comprehensive location data (per Carpenter II)
Whether evidence should be suppressed despite the Fourth Amendment violation	Suppression required because constitutional violation occurred	Agents acted in objectively reasonable good-faith reliance on the SCA and magistrate orders; exclusionary rule inapplicable	Suppression denied: good-faith exception applies because reliance on § 2703(d) was objectively reasonable (affirmed)

Carpenter v. United States, 138 S. Ct. 2206 (2018) (CSLI is a Fourth Amendment-protected search; warrant generally required)
United States v. Leon, 468 U.S. 897 (1984) (good-faith exception to the exclusionary rule for reliance on a defective warrant)
Illinois v. Krull, 480 U.S. 340 (1987) (extends Leon good-faith principle to reasonable reliance on a statute later held unconstitutional)
United States v. Jones, 565 U.S. 400 (2012) (government tracking of movements implicates Fourth Amendment privacy concerns)
United States v. Warshak, 631 F.3d 266 (6th Cir. 2010) (agents reasonably relied on § 2703(d) to obtain emails; relevant to good-faith analysis)
United States v. Frazier, 423 F.3d 526 (6th Cir. 2005) (discusses standards for applying Leon good-faith exception)