A Virginia state judge ruled last week that law enforcement may require a criminal defendant to provide his fingerprint — but not his passcode — to unlock a smartphone that might contain evidence that would be used against him at trial.

In Commonwealth v. Baust, the police sought access to the smartphone of David Charles Baust, who was indicted in connection an alleged assault. The victim alleged that a video of the assault was stored on Baust’s phone.

Police officers obtained a warrant for the phone and other evidence from Baust’s home. Because the officers were unable to unlock Baust’s phone, the government filed a motion to compel Baust to produce either his passcode or fingerprint to unlock the phone.

Because the government had obtained a lawfully executed search warrant, Baust could not challenge the government’s request on Fourth Amendment grounds. Instead, Baust argued that the request violates the Fifth Amendment, which provides that no person “shall be compelled in any criminal case to be a witness against himself.” Courts have long held that this privilege protects a criminal defendant from being forced to provide the government with “evidence of a testimonial or communicative nature.”

Virginia Circuit Court Judge Steven C. Frucci rejected the government’s request to compel Baust to provide his passcode, holding that providing his passcode would be testimonial because it would force Baust to “disclose the contents of his own mind.” This conclusion is in line with a 2010 ruling by a Michigan federal court that forcing the defendant to produce a passcode is “the extortion of information from the accused.”

But Judge Frucci allowed the government to compel Baust to provide his fingerprint. He concluded that the fingerprint, “like a key . . . does not require Defendant to communicate any knowledge at all.”