As the world watched the FBI spar with Apple this winter in an attempt to hack into a San Bernardino shooter's iPhone, federal officials were quietly waging a different encryption battle in a Los Angeles courtroom.
There, authorities obtained a search warrant compelling the girlfriend of an alleged Armenian gang member to press her finger against an iPhone that had been seized from a Glendale home. The phone contained Apple's fingerprint identification system for unlocking, and prosecutors wanted access to the data inside it.
It marked a rare time that prosecutors have demanded a person provide a fingerprint to open a computer, but experts expect such cases to become more common as cracking digital security becomes a larger part of law enforcement work.
The Glendale case and others like it are forcing courts to address a basic question: How far can the government go to obtain biometric markers such as fingerprints and hair?
The U.S. Supreme Court has held that police can search phones with a valid warrant and compel a person in custody to provide physical evidence such as fingerprints without a judge's permission.