MN Supreme Court: OK to demand suspect’s fingerprint to unlock phone

You’re not protected by the Fifth Amendment’s right against self-incrimination when a judge orders you to use your fingerprint to unlock your cellphone, the Minnesota Supreme Court ruled Wednesday.

The state’s high court backed a January 2017 ruling by the Minnesota Court of Appeals in the case of Matthew Vaughn Diamond, who had been convicted by a jury of burglary and theft charges in the break-in of a home in Chaska and sentenced to 51 months in prison.

In the investigation, a detective had obtained a search warrant for Diamond’s cellphone but was unable to unlock it, so a judge ordered Diamond to use his fingerprint to unlock it. Diamond challenged the order, arguing it violated his constitutional right not to incriminate oneself.

His attorney argued that by unlocking the cellphone, Diamond was providing incriminating information.

Minnesota justices on Wednesday, though, said that while the Fifth Amendment bars a state from forcing “oral and physical testimonial communications from a defendant,” that’s different than seeking physical evidence, like a fingerprint.

“Diamond merely provided his fingerprint so that the police could use the physical characteristics of the fingerprint to unlock the cellphone,” the court wrote. Since using a warrant to get physical evidence from Diamond’s body “did not reveal the contents of his mind, no violation of the Fifth Amendment privilege occurred.”