A federal District Court in California has decided that police cannot force individuals to unlock their smartphones by using their biometric features. The decision was delivered in the court’s denial of a request for a search warrant, as part of an investigation of an alleged blackmail scheme carried out through the use of Facebook. The court was asked to order those present at a given residential property to unlock their phones by face recognition, fingerprint or iris scan.

Although the court found sufficient probable cause to issue a warrant to search the property, it determined that the police does not have the right to open the smartphones held in the property by forcing those present to use their biometric identification features. The court noted that forcing suspects to incriminate themselves by unlocking their devices constitutes a violation of their Fifth Amendment rights. The court relied on Supreme Court decisions holding that the Fifth Amendment privilege against self-incrimination bars compelling a suspect to provide testimonial evidence. The court’s decision takes those Supreme Court holdings a step further by determining that just like a person cannot be compelled to disclose a smartphone passcode because it is testimonial in nature, a person cannot be compelled to provide their finger for the same purpose of unlocking the smartphone.

The Court also explained that despite the obvious investigative interest of the authorities in gaining access to the phones’ content, there are other ways to gain such information that “do not trample on the Fifth Amendment". The court suggested obtaining a warrant for the communications made in the course of the suspected blackmail from Facebook.

CLICK HERE to read federal court’s decision.