U.S. judge allows law enforcement to compel suspect to unlock smartphone with biometrics

Apr 26, 2019 | Chris Burt

A U.S. federal district court judge in Massachusetts has ruled that agents of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) can force people to unlock their smartphones with fingerprint biometrics in the execution of a search warrant, The Register reports.

Judge Judith Dein approved the warrant to search the property of a suspected firearms trafficker, including any iPhone found at his Boston apartment. Three of ten paragraphs in the warrant relate to the suspect’s Apple device and the authorization of law enforcement to try his fingers on any iPhone which may belong to him.

The affidavit notes that communications with cell phones are among the evidence that led to the identification of the suspect, and that his iPhone could therefore reasonably be expected to contain evidence of illegal activity. The officer providing the affidavit also points out that the biometric unlocking method is necessary because otherwise the device can only be unlocked with the password, which the suspect would have to voluntarily provide. Passwords are considered potentially self-incriminating testimony, and therefore are protected by the Fifth Amendment, which led a forensics consultancy to advise law enforcement to try to preserve the possibility of biometric unlocking for seized devices last year.

A California judge recently ruled that U.S. police cannot compel people to unlock devices with their facial or fingerprint biometrics, arguing that biometrics are equivalent to the physiological responses of lie-detector tests, which are considered testimony. A similar point was made in a 2017 ruling in an Illinois federal court case.

The Register reports, however, that the Massachusetts Supreme Judicial Court ruled last month that a password is not testimony, as neither it nor the contents of the device it unlocks constitutes new information. In that case, Justice Barbara Lenk, while agreeing with the decision, warned that “the court’s decision today sounds the death knell for a constitutional protection against compelled self incrimination in the digital age.”

Previous court decisions have been split on whether passwords are testimony, and whether biometrics are equivalent to passwords in this sense, suggesting that ultimately, the questions will have to be resolved by the Supreme Court.