United States v. White Google Pixel 3 XL cellphone in a black Incipio case, 398 F.Supp.3d 785

Federal agents executed a valid search warrant at a residence investigating possession of child pornography and seized a locked Google Pixel 3 XL found in a bathroom.
The phone could be unlocked by passcode or fingerprint; biometric unlocking via fingerprint works for 48 hours since last unlock.
After seizure, the government sought a supplemental warrant authorizing officers to compel the subject to press any finger/thumb to the phone’s fingerprint sensor to unlock it.
A Magistrate Judge denied that supplemental warrant, concluding compelling a fingerprint to unlock the phone would violate the Fifth Amendment privilege against self-incrimination (and thus the Fourth Amendment).
The government moved for district-court review; the district court found the issue moot for the particular phone (biometric window expired) but entertained the case under the ‘‘capable of repetition, yet evading review’’ exception.
On the merits the district court vacated the magistrate judge’s order and granted the government’s motion, holding that compelling a fingerprint is non-testimonial and does not violate the Fifth Amendment.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether compelling a suspect to provide a fingerprint to unlock a phone violates the Fifth Amendment	Government: fingerprint is a physical characteristic (non-testimonial); no Fifth Amendment violation	Individual/Magistrate: compelled fingerprint is testimonial authentication and self-incriminating	Court: No Fifth Amendment violation; fingerprint is non-testimonial
Whether the case is moot and reviewable	Government: exception applies — capable of repetition yet evading review; district review appropriate	Implicit: issue moot for this device because fingerprint window expired	Court: Moot as to this phone but exception applies, so decision on merits allowed
Whether compelling biometric unlock also violates Fourth Amendment	Government: if no Fifth Amendment problem, the search is reasonable under warrant	Magistrate: Fifth Amendment violation would make the search unreasonable under Fourth Amendment	Court: Because no Fifth Amendment violation, the compelled biometric search under warrant comports with Fourth Amendment reasonableness
Whether a district split in the district of Idaho justified review as well	Government: magistrate rulings show split warranting district review	Court/defense: no published contrary decisions; magistrate signings alone not a reasoned split	Court: Declined to rely on a claimed intra-district split; decided on merits via mootness exception

Doe v. United States, 487 U.S. 201 (1988) (distinguishes surrender of physical key from compelled disclosure of a combination; testimonial inquiry centers on contents of the mind)
United States v. Hubbell, 530 U.S. 27 (2000) (explains testimonial vs. physical-act distinction under the Fifth Amendment)
Hiibel v. Sixth Judicial Dist. Court, 542 U.S. 177 (2004) (defines elements of Fifth Amendment privilege: testimonial, incriminating, compelled)
Schmerber v. California, 384 U.S. 757 (1966) (compelled physical samples such as blood held non-testimonial)
United States v. Wade, 388 U.S. 218 (1967) (compelled fingerprints, photographs, voice exemplars treated as non-testimonial)
Fisher v. United States, 425 U.S. 391 (1976) (foregone-conclusion doctrine: government may subpoena documents when existence/possession are a foregone conclusion)
Andresen v. Maryland, 427 U.S. 463 (1976) (discusses compelled authentication and testimonial evidence)
County of Los Angeles v. Davis, 440 U.S. 625 (1979) (mootness principles for equitable relief)