On Tuesday, the 11th Circuit handed down a new computer search decision, United States v. Johnson, that both sharpens and deepens the circuit split on how the private search doctrine of the Fourth Amendment applies to computers. Johnson isn’t a likely candidate for Supreme Court review. But it does leave the private search doctrine in computer searches ripe for Supreme Court review in other cases working their way through the courts.

Here’s a quick summary of the issue, which I first wrote about in detail in a 2005 article. Because the Fourth Amendment applies only to the government and its agents, the Fourth Amendment is not triggered when private parties not associated with the government conduct searches. When a private party conducts a search and finds evidence of crime, the private party often goes to the police and voluntarily shows the police what she has found. The Supreme Court uses what I have called the “private-search reconstruction” doctrine to regulate what the police are allowed to see without a warrant. The police can reconstruct the private party search, seeing what the private party saw, but they can’t exceed the search the private party conducted.

On to the important legal question: When a private party searches a computer, sees a suspicious file and reports the finding to the police, what kind of government search of the computer counts as merely reconstructing the private search and what kind of search counts as exceeding the private search? The question comes up frequently in cases involving images of child pornography discovered on a phone, laptop or storage drive. The issue boils down to identifying the right unit of measurement to describe the private search. For example, if the private party saw one file in one folder in the computer, should we say that only the one file was searched, so that the police can see only that one file, and anything else exceeds the private search? If only part of the file was observed, should we say that the police can see only the part of the file that was observed? Alternatively, should we say that the one folder was searched, so the police can see anything in that folder? Or should we say that the entire computer was searched, so the police can search the entire computer?

In 2005, the 5th Circuit ruled that the entire computer was searched. In 2012, the 7th Circuit agreed with the 5th Circuit that the entire computer was searched. In May, the 6th Circuit handed down a ruling concluding that the unit should be data or the file, so that government observation of anything not actually viewed by the private party exceeds the scope of the private search.

The new case, Johnson, also adopts the data or file approach — thus deepening the 2-1 split into a 2-2 split.

Here’s a sanitized version of the facts (which in unsanitized form are, unfortunately, very disturbing). A cellphone was accidentally left at a Wal-Mart. The phone was not password-protected, and a Wal-Mart employee looked through the phone. She found some disturbing images and told her fiance Widner about what she had seen. Widner scrolled through all of the thumbnail images in a photo album found in the phone. He also stopped and opened a few images to full size, and he watched one video. Widner then turned over the phone to law enforcement. Widner showed investigators what he had seen. Later on, a police detective named O’Reilly went through the folder and opened all of the images to full size and watched both the video Widner had seen and another video Widner had not seen.

The 11th Circuit holds that (1) the officer did not exceed the scope of the private search when he looked at the photos, including full-size images of files Widner had only seen as thumbnails, or when he watched the video Widner had viewed, but that (2) the officer did exceed the scope of the private search, and therefore violated the Fourth Amendment, when he watched the video that Widner had not watched. “To the extent that O’Reilly viewed the second video, which was stored within the same album that Widner had scrolled through but which Widner did not view,” the court rules, “O’Reilly exceeded the scope of Widner’s private search.”

Here’s the complete analysis:

The district court relied on United States v. Simpson, 904 F.2d 607 (11th Cir. 1990), in holding that O’Reilly’s viewing of the second video did not exceed the scope of Widner’s search, even though Widner had not reviewed that particular video. Though we find Simpson to be analogous to the facts here as they regard O’Reilly’s review of the photos and the video that Widner had previously seen, we conclude that Simpson cannot justify O’Reilly’s viewing of the second video.

In Simpson, FedEx employees opened a package that was missing an address label to try to determine a destination for the package. Id. at 610. A company security officer viewed four videotapes from the package and concluded that they contained sexually explicit material in which some of the actors appeared to be minors. See id. An Assistant United States Attorney and an FBI agent later viewed the same four videotapes. See id. We held that the government officials “did not exceed the scope of the prior private searches for Fourth Amendment purposes simply because they took more time and were more thorough than the Federal Express agents.” Id. at 610.

We agree that under Simpson, O’Reilly’s review of the photos and the video that Widner watched did not violate the Fourth Amendment. Though O’Reilly may have looked at some of the photos and the video more closely than did Widner, as with the videotapes in Simpson, the private party’s earlier viewing of the same images and video insulated law enforcement’s later, more thorough review of them from transgressing the Fourth Amendment.

But with respect to the second video, which Widner never watched, O’Reilly’s review exceeded—not replicated—the breadth of the private search. Nothing in Simpson provides a safe harbor for a governmental search of materials beyond the scope of a private search.

We also have serious doubts that approving of O’Reilly’s viewing of the second video when no private party had first watched it would be consistent with the reasoning in Riley v. California, ___ U.S. ___, 134 S. Ct. 2473, 2489-90 (2014). In Riley, the Supreme Court held that law enforcement must obtain a search warrant to search a cell phone seized incident to arrest, unless exigent circumstances apply. Id. at 2494-95. In reaching this conclusion, the Court emphasized that cell phones “hold for many Americans ‘the privacies of life.’” Id. (citation omitted). It further observed the tremendous storage capacity of cell phones and the broad range of types of information that cell phones generally contain, suggesting that a search warrant for a cell phone must specify what part or parts of the information contained on it may be searched. Id. at 2489. While Widner’s private search of the cell phone might have removed certain information from the Fourth Amendment’s protections, it did not expose every part of the information contained in the cell phone. Here, no search warrant was obtained, and no exception to the search-warrant requirement excused O’Reilly’s viewing of the second video.

The 11th Circuit has adopted a data-based approach, it seems to me. Widner had scrolled through the folder, so he would have seen a still image from the video. But observing just part of the file didn’t mean that Widner had searched the entire file; what Widner had not actually seen remained unsearched. It’s less obvious that looking at a full-size image doesn’t reveal data not already seen by a thumbnail image, but that matches the conclusion of the 9th Circuit in an earlier case. See United States v. Tosti, 733 F.3d 816 (9th Cir. 2013) (holding that when an officer reconstructed a private search, clicking on a thumbnail and seeing the larger image did not exceed the scope of the private search where “the police learned nothing new through their actions”).

The basic approach is correct, in my view, for reasons I explained in my 2005 article, “Searches and Seizures in a Digital World.”

The Supreme Court won’t be interested in settling this split in Johnson itself. The 11th Circuit went on to conclude that the violation made no difference because the warrant eventually obtained was based on the other evidence and not that one video. But Johnson further deepens the split on how the private search doctrine applies, making it now pretty ripe for Supreme Court review in another case in the not-too-distant future.