University of Southern California

Get a Warrant: A Bright-Line Rule for Digital Searches Under the Private-Search Doctrine


Note by Dylan Bonfigli
From Volume 90, Number 2 (January, 2017)

A girlfriend hacks her boyfriend’s computer and discovers evidence of tax evasion. She contacts a local law enforcement officer who arrives at her house and looks at the files she found. Without a warrant, the officer opens other files in the same folder the girlfriend had searched. The officer notices another folder labeled “xxx.” He opens the folder and discovers child pornography. The officer seizes the computer based on what he found. The boyfriend is indicted for possession of child pornography and tax evasion. Before trial, the boyfriend moves to suppress all evidence obtained pursuant to the officer’s warrantless search of the computer. What evidence should the judge suppress?

The answer turns on the Fourth Amendment’s private-search exception. Under this exception, a government agent may recreate a search conducted by a private individual so long as the agent does not “exceed the scope” of the prior private search. The question under the existing framework is: at what point did the officer exceed the scope of the prior search—if at all? Was it when he viewed files the girlfriend had not viewed, when he opened files in a different folder, or did he stay within the scope of the girlfriend’s search by only searching the computer’s hard drive? This is what I will refer to as the denominator problem, which asks what courts should use as the unit of analysis to measure the scope of a digital search.

There are at least four competing approaches to the denominator problem, discussed in Part II, and the Supreme Court has provided little guidance on how the private-search doctrine applies to digital searches, resulting in a circuit split. Until this issue is resolved, law enforcement has little guidance on when to obtain a warrant following a private search and can unknowingly subject individuals to unreasonable invasions of privacy, which may result in suppression of relevant evidence. One recent example is United States v. Lichtenberger.

In Lichtenberger, the Sixth Circuit adopted a narrow approach to defining the scope of digital searches and held that a police officer exceeded the scope of a prior search because there was no “virtual certainty” that his search would reveal the same data exposed in the private search. The decision came shortly after and discussed the recent Supreme Court case Riley v. California, which recognized that society has a heightened interest in digital information stored on a cell phone. The Sixth Circuit did, however, refuse to extend laptops the same protection that it provides private dwellings—exemption from the private-search doctrine. I disagree with this holding.

This Note rejects the four existing approaches and argues that the private-search exception should not allow warrantless digital searches because society’s significant privacy interest in information stored on digital devices outweighs any legitimate government interest in a warrantless search of that device. Instead of using the traditional private-search framework, the Sixth Circuit should have created a bright-line rule, as the Supreme Court did in Riley, exempting digital searches from the private-search doctrine. This approach would require law enforcement to obtain a warrant before reconstructing a private search of digital information.

To support this argument, I distinguish society’s privacy interest in digital storage devices from the physical container the Supreme Court based the private-search doctrine on. I will also draw an analogy between digital storage devices and homes, focusing on cases in which courts have refused to extend the private-search exception to private dwellings. At first blush, this approach may appear to be anti-law enforcement, but as I discuss in Part III, law enforcement stands to lose very little from this approach and gains a great deal of clarity when compared to the existing approaches.


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