Nov. 25, 2025 – In what may be the first case of its kind, the Wisconsin Court of Appeals in State v. Melssen, No. 2024AP1942-CR (Nov. 20, 2025) (recommended for publication) vacated an order denying suppression of evidence obtained from an overly broad search of a smartphone.

Presiding Judge Rachel A. Graham, writing for the unanimous three-judge panel, concluded “the warrant to search [Emil] Melssen’s smartphone – which authorized officers to search virtually all of the messages, images, search terms, passwords, correspondence, credit card bills, telephone bills, digital artifacts, and incoming and outgoing telephone numbers and call details stored on the smartphone – violated the Fourth Amendment because it was overbroad and not carefully tailored to its justifications.”

The panel included Judge Brian W. Blanchard and Judge JoAnne F. Kloppenburg.

The Court of Appeals remanded the case to Lafayette County Circuit Court to determine whether evidence found on the smartphone and a search of Melssen residence based on the smartphone evidence must be suppressed, and whether Melssen’s is entitled to a new trial.

Text Messages in the Ambulance

Reports that Melssen and a victim injured each other on May 25, 2021, outside the home of the victim’s girlfriend, began a police investigation.

Police learned that Melssen and the victim’s girlfriend talked to each other on the phone before the physical conflict, and Melssen had sent her multiple text messages while he was in the ambulance.

The victim also suggested his girlfriend and Melssen were in touch by text messages and phone calls, and “are constantly communicating about drugs and refer to drugs as ‘groceries.’”

Officers seized Melssen’s smartphone and sought a warrant for evidence of “battery, domestic abuse incidents, and/or narcotic activity.”

The affidavit justifying probable cause detailed facts about the battery in 11 paragraphs.

The affidavit justified the search for drug violations by the victim’s statement and that the officer knew “from prior law enforcement investigations” that the girlfriend was “a drug user” who lived where methamphetamine had been sold.

Officers wanted to search the phone to “reveal valuable information to establish a timeline for investigating officers to establish an accurate record of events.”

‘Narcotic Activity’

The circuit court issued the warrant for searches of images or visual depictions, search terms, telephone calls, and correspondence, as well as passwords, ownership, and technical data.

Text messages found between Melssen and individuals identified as “Becky” and “Bill’s Girlfriend” “could support the reasonable inference that Melssen was involved” in drug distribution.

Police obtained a warrant to search Melssen’s residence, where they found “methamphetamine, drug paraphernalia, and items consistent with drug distribution.” A locked vehicle on the property contained methamphetamine.

After being charged with drug crimes, Melssen moved to suppress the evidence from the searches for lack of probable cause.

“Melssen argued that this ‘scant factual evidence’ did not justify the search that police conducted, which amounted to a ‘general search’ of his ‘entire phone.’”

The state in defense “focused almost exclusively on the battery,” saying that “common sense would cause a person to infer that this incident may be drug related.”

The circuit court denied Melssen’s motion, based in part “that it would have been impractical to authorize a more limited search because investigators have to ‘walk through an entire cell phone … to find what it is that [they]’re looking for.’”

The jury found Melssen guilty on all drug-related charges. Charges related to the battery involve another case also on appeal.

Digital Particularity

The Fourth Amendment prohibits “unreasonable searches and seizures,” requiring warrants “upon probable cause” and “particularly describing the place to be searched.”

The search must be “carefully tailored to its justifications, and will not take on the character of the wide-ranging exploratory searches the Framers intended to prohibit.”

“There are no United States Supreme Court cases, and no published Wisconsin cases,” the Court of Appeals said, “that have addressed what the dual mandates of the Warrant Clause require of an application for a warrant to search the contents of a smartphone.”

Cases involving searches of smartphones and computers provided guidance.

“The concern about indiscriminate searches of residences by government actors is at the core of the Fourth Amendment,” the Court of Appeals explained, and the U.S. Supreme Court “observed that smartphones contain personal and sensitive information far beyond what would be found in a residence ‘in any form.’”

Cases about searches of computers advise that “the particularity requirement must be carefully applied when analyzing governmental searches,” the decision noted from federal cases in other states and the U.S. Court of Appeals.

“[A]n unlimited search of a person’s smartphone would reveal private details of the person’s life that are wholly unrelated to any criminal investigation that justified the search,” Graham wrote, such as about medical conditions, confidential communications, and private writings.

“For all of these reasons,” the Court of Appeals explained, “we do not agree with the circuit court’s conclusion that, to the extent there is probable cause that evidence of a crime will be found on a smartphone, this necessarily means that there is probable cause for an essentially unrestricted search of the smartphone’s contents.”

As federal and state courts have held in seven states and the District of Columbia, the Court of Appeals warned that “a warrant to search a smartphone must be ‘carefully tailored to its justifications.’”

Demands of particularity require searches limited by specified types of data and time periods, the court explained.

‘Exceptionally Vague and Exceedingly Slim’

In applying these principles, the Court of Appeals concluded that the affidavit documented sufficient probable cause for a smartphone search in the battery investigation.

“This does not end our inquiry,” the court cautioned.

Only the call log on May 25, 2021, communications with the girlfriend on that date, and communications “immediately following the altercation” found support in the affidavit, the Court of Appeals said.

“[T]he affidavit did not reasonably suggest,” the court warned, any other data on the smartphone would reveal evidence: no inference of photos or videos, communications, and no justification for an unlimited time period for the search.

For the battery investigation, the warrant was overbroad, the appellate court held.

The warrant fared worse for the narcotics investigation, for which “the averments … were exceptionally vague and exceedingly slim,” the Court of Appeals said.

Evidence that the two communicated about drugs using the term “groceries” – even with “a known drug user” – is not a crime, the court explained.

The circuit court appeared to rely on what it knew from previous criminal proceedings against Melssen, the Court of Appeals noted, but “this information was not included in the warrant application, and we do not consider these additional allegations in our analysis.”

The Court of Appeals concluded “that the warrant to search Melssen’s smartphone authorized a far more extensive search than was allowed by the Warrant Clause’s dual mandates of probable cause and particularity.”

On appeal, the state argued that Fourth Amendment good faith and plain view exceptions allow the evidence, but, the Court of Appeals noted, the state never had the opportunity to argue that before the circuit court.

“[W]e do not resolve the potentially fact-intensive issues surrounding the determination of whether the text messages found in the resulting search must be suppressed,” the Court of Appeals said.

Because the faulty smartphone search justified searching the residence, “we also do not determine whether they could be used as probable cause to support the residence warrant,” the Court of Appeals concluded.

Those issues remained for the circuit court on remand.