Can warrants for digital evidence also require fingerprints to unlock phones?

There has been a lot of press coverage recently about a search warrant obtained in Los Angeles allowing the government to force people present when the warrant is executed to press their fingers and thumbs on the fingerprint sensors of any phones or computers found there to unlock them. A lot of people have wondered: Is that legal? I don't think there's an easy answer to that. Here's an overview of some of the legal issues.

First, an important caveat: It's hard to draw conclusions about the legality of the warrant because we know so little about it. All we have is a seven-page memo in which the government makes the case for the warrant, plus word from Thomas Fox-Brewster (who broke the story) that the warrant was later executed at a residence. We haven't seen the warrant, and we don't know what it says. We don't know what happened when the warrant was executed. So we don't have much information yet.

With that said, I have some preliminary thoughts on the question. The short version is, I think this raises a bunch of hard issues. Here are some details for those who want the longer version.

First, I understand Ybarra v. Illinois to hold that the government can't search a person present where the warrant is executed for evidence under the warrant unless the government has probable cause that this particular person is involved in the criminal activity. Under Ybarra, the government can't just go in and grab the phones from the pockets of everyone in the home; it needs probable cause as to each person to search him. And that's true regardless of whether the phones are locked or unlocked. It's a limitation on the search of people that gets to the seizure of the phone, not a search of the phone after it has been seized.

Let's assume that the government can get beyond the Ybarra problem, either because it has probable cause and searches that person to find the phone or the phone (or other computer) is in the house but not on the person. Can it order a person present to unlock a phone? There will be some circumstances where that raises Fifth Amendment issues. I suspect, though, that those issues will come up only occasionally for a practical reason: Because executing a warrant usually does not lead to a situation of Miranda custody for people present, and under Salinas v. Texas the Fifth Amendment privilege is unavailable outside of Miranda custody unless the person formally asserts it, any Fifth Amendment issues would come up only when the officer tells the person to unlock the phone and the person responds by formally asserting his right to silence (or else the person is already under arrest).

An additional question is whether the government can get around any Fifth Amendment issues by having targets place their fingers on the phones rather than entering in passcodes. I think the answer is, "often yes, but not always." If the officers tell the person to place a particular finger on the phone, the response will not be testimonial. Complying with an order to place a particular finger on a particular phone does not amount to a statement about something, so the Fifth Amendment will not apply.

On the other hand, if the officers find a phone and tell a suspected owner to unlock the phone with his finger, responding to the order may imply testimony. By responding to the order by picking the finger that was selected to unlock the phone, the person is admitting that it is his phone. [Update: Thanks to Andrew Crocker and Marcia Hofmann for helping to make that point.] A suspect who asserts his right to silence at that point, or who is already under arrest and has Miranda rights, might have a case. With that said, that shouldn't be a problem under the foregone conclusion doctrine if the government already knows that it is the person's phone. But with that said, some courts have taken a different view on the standard for that, and it remains somewhat uncertain. So the Fifth Amendment issues there remain somewhat murky. (You might wonder: Why won't the government just have the person try every finger on every phone? I suspect the problem is that fingerprint access often disables after a few tries, so the government needs a more targeted approach.)

Now let's assume that the government has overcome the Ybarra problem and also the Fifth Amendment issue. The next issue is: Can the government force a person to press his fingers on the phone to unlock it? There is support in the caselaw, recited in the government's memorandum, that reasonable suspicion that the person committed a crime is sufficient for the government to seize a person to get a fingerprint. But it's not clear that reasonable suspicion is the right standard for this, as the existing caselaw involves getting a fingerprint to establish guilt or innocence rather than to facilitate a search.

The government rightly points out that existing caselaw allows the government to seize keys and other tools needed to facilitate searches. But it's not obvious what the standard is when the key is a person's body. The problem is that Ybarra suggests that a different question is presented when the government searches a place for evidence vs. when it searches a person who is in the place. Maybe the standard should still be reasonable suspicion, but maybe it's something else. And if the standard is reasonable suspicion, reasonable suspicion of what? I understand the fingerprint cases to say that reasonable suspicion there is that the person has committed a crime. In contrast, the warrant here talks about reasonable beliefs that the person is a user of the device found at the place. That's a very different question.

Also, there's a procedural issue of whether this belongs in the warrant. If a judgment of reasonable suspicion has to be made, should it be built into the warrant, or is it just something that the officers have to evaluate on the scene subject to later review? In the Ninth Circuit, where this warrant was obtained, I can understand why the officers sought out explicit permission: In United States v. Hill, 459 F.3d 966 (9th Cir. 2006), the Ninth Circuit indicated that getting magistrate preapproval for search methods was favored. But it's not clear to me that blanket approval in the warrant makes sense, as compared with a case-by-case determination of cause in the course of the execution.

Finally, for the seven readers still following me - congrats, you just won a Volokh Conspiracy T-shirt! - I should point out that this is another novel legal question raised by an encryption workaround. When the police expect to seize locked phones from a house, and the homeowners are likely there, that initial physical search stage is an obvious opportunity to try to get help unlocking the phones.