WASHINGTON — The Justice Department will ask Apple for help in unlocking an iPhone belonging to one of the shooters who carried out the Dec. 2. San Bernardino, Calif., terrorist attacks, according to a court order signed Tuesday.

The order does not ask Apple to break the phone’s encryption, but rather to disable the feature that wipes the data on the phone after 10 incorrect tries at entering a password. That way, the government can try to crack the password using “brute force” – attempting tens of millions of combinations without risking the deletion of the data.

The order, signed by a magistrate judge in Los Angeles, comes a week after FBI Director James B. Comey told Congress that the bureau has not been able to open one of the killers’ phones. “It has been two months now, and we are still working on it,” he said.

The issue illustrates the frustration of law enforcement in gaining access to data in high-profile investigations, and raises the pressure on Apple to find a way to comply as the phone in question was used in the deadliest terrorist attack on U.S. soil since Sept. 11, 2001.

The Silicon Valley giant has steadfastly maintained it is unable to unlock its newer iPhones for law enforcement, even when officers obtain a warrant, because they are engineered in such a way that Apple does not hold the decryption key. Only the phone’s user would be able to unlock the phone – or someone who knew the password.

The FBI’s efforts may show just how impervious the new technology is to efforts to circumvent it. According to industry officials, Apple cannot unilaterally dismantle or override the 10-tries-and-wipe feature. Only the user or person who controls the phone’s settings can do so.

The phone was used by Syed Rizwan Farook, who, with his wife Tashfeen Malik, opened fire at a holiday party at the Inland Regional Center, killing 14 people. The couple, who had pledged loyalty to the Islamic State, died a few hours later in a shootout with police.

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