MADISON, Wis. (CN) - The Wisconsin Supreme Court unanimously ruled Wednesday that law enforcement does not need a warrant to view child pornography reported by social media platforms.

Snapchat discovered a 16-second video depicting child sexual abuse in January 2023, uploaded by Michael Gasper using a third-party software.

The platform's terms of service state content like Gasper uploaded would be removed and reported to the National Center for Missing & Exploited Children. The content was passed to the Wisconsin Department of Justice, where it was actually viewed for the first time without a warrant.

Gasper successfully argued in Waukesha County Circuit Court that investigators violated his Fourth Amendment protection against warrantless search and the video was tossed as evidence.

An appellate court reversed, finding Gasper had no reasonable expectation of privacy because he violated Snapchat's terms of service.

Gasper appealed and renewed his argument before the state's high court in September 2025.

On Wednesday, the Wisconsin Supreme Court affirmed on slightly different grounds and revived the evidence against Gasper.

"The Fourth Amendment does not protect Gasper from a private actor who discovers that CSAM has been uploaded to its platform," Justice Annette Ziegler wrote for the majority in a 24-page opinion, using the acronym for child sexual abuse material. "The government did not conduct a warrantless search of Gasper's cellphone or his Snapchat account, it merely reviewed the full CyberTip which included the video,"

The high court's reasoning differed from the appellate ruling, which turned on Gasper's expectation of privacy, by focusing instead on whether the government went beyond the private search conducted by Snapchat.

Gasper acknowledged the video involves child sexual abuse and he didn't argue the government searched more than the single video contained in the CyberTip. Instead, he argued no one at Snapchat physically watched the video before sending it to law enforcement.

Snapchat employs Microsoft's PhotoDNA software to perform sweeps for child sexual abuse material using hash-value matching. A hash-value is a string of letters and numbers created by a computer that correspond to the file's contents.

PhotoDNA compares the hash-values to Google's child sexual abuse material hash-value database, allowing Snapchat to root out content without subjecting an employee to offensive or illegal images.

The hash-value system creates a "virtual certainty that law enforcement would not find anything of significance beyond what the private search revealed," the court found. Even if PhotoDNA is unreliable, which Gasper did make the case for, the court said it wouldn't matter.

"The Miller court stated, and we agree, that 'just because a private party turns out to be wrong about the legality of an item that the party discloses to police does not mean that the police violate the Fourth Amendment when they reexamine the item,'" Ziegler wrote.

This case kicked off the Wisconsin Supreme Court's 2025-26 term and was heard back-to-back with another child sexual abuse material case involving a Google Photos account. In that case, Andreas Rauch Sharak claimed Google acted as an agent of the government when it scanned his account for child pornography.

During oral arguments, Justice Rebecca Bradley suggested Snapchat's scheme supports the Founders' intent, using a hypothetical image presented by Gasper's attorney Joseph Owens involving underage characters from the Peanuts cartoon strip engaging in sexual activity.

"Law enforcement under this paradigm can say, 'thanks for reporting but its just a cartoon.' The alternative is they get a warrant for somebody's house and rifle through every laptop and drawer. That is what the Founders were trying to protect us all from," Bradley said.

Several justices filed concurring opinions, but Justice Rebecca Frank Dallet wrote the majority's opinion weakens Fourth Amendment protections by misapplying the private search doctrine.

Though Dallet agreed Gasper's motion to suppress should have been denied, she accepted Gasper's argument that the hash-value match does not reveal to Snapchat what exactly happened on the video, so the state investigator exceeded the scope of Snapchat's search.

Owens said he felt deflated reading the complicated opinion but was impressed by the judicial scholarship exhibited. The case will return to the Waukesha County Circuit Court, where he said he will challenge the search warrant executed on Gasper's home and electronic devices.

The warrant did not give police the authority to unlock and search Gasper's laptop and cellphone, Owens said, but the lower court opted to resolve the dispositive private search issue before reaching the second Fourth Amendment challenge.  

Source: Courthouse News Service