Warrant Not Required To Obtain Single Location Point From Suspect’s Cellphone App

Police did not need a search warrant to receive data from a mobile phone app.

Police did not need a search warrant to receive data from a mobile phone app.

A person voluntarily inputting information into an online marketplace phone app has no reasonable expectation of privacy in that information, meaning that law enforcement does not need a search warrant from a magistrate to get such information, the Supreme Court of Ohio ruled today.

In a unanimous decision, the Supreme Court held that a Columbus police detective’s use of a warrantless subpoena did not violate the Fourth Amendment rights of Mamadou Diaw, a man suspected of using the Letgo marketplace app to set up a robbery.

The Franklin County Common Pleas Court suppressed information provided by Letgo in response to the subpoena. The Tenth District Court of Appeals reversed the decision, holding that law enforcement did not need a warrant to get the single, historical data point from Letgo. The Supreme Court affirmed that decision.

Writing for the Court, Chief Justice Sharon L. Kennedy explained the U.S. Supreme Court has developed the “third-party doctrine,” which states that people have no reasonable expectation of privacy in nonconfidential information that they voluntarily turn over to others.

“Having voluntarily conveyed his location to Letgo in the ordinary course of using the app, Diaw cannot now assert a reasonable expectation of privacy in that information,” she wrote.

Suspect Tracked Down Online
In February 2020, a man identified in court records as “K.W.” agreed to buy a laptop from a seller on Letgo who was operating under the alias John Malick. Diaw was using the alias Malick and met K.W. in a parking lot. When K.W. entered Diaw’s vehicle, Diaw stole K.W.’s iPhone and the money the victim brought to exchange for the laptop. Diaw pulled the laptop away from K.W. and began punching him. Diaw’s accomplice pointed a gun at K.W., who exited the vehicle. Diaw then pushed K.W. to the ground and repeatedly kicked him.

Columbus Police Detective Michael Sturgill investigated the matter. R.C. 2935.23 allows law enforcement to subpoena witnesses after a felony has been committed, but before any arrest has been made. Sturgill sent a subpoena to Letgo seeking information regarding the customer using the name John Malick to sell a laptop in Columbus during a three-day period in February 2020. Letgo provided an IP address of the device using Letgo, the email address associated with the name John Malick, and a single GPS latitude and longitude point. Sturgill found that the location data point corresponded with a McDonald’s in Columbus, which he would later learn is adjacent to Diaw’s apartment.

Sturgill collected other information that led to the arrest of Diaw, who was charged with aggravated robbery and robbery. In court, Diaw sought to suppress the evidence provided by Letgo. The trial court ruled the police violated Diaw’s rights under the Fourth Amendment to the U.S. Constitution. The Fourth Amendment prohibits unreasonable searches and seizures. The Franklin County Prosecutor’s Office appealed the decision to suppress the evidence to the Tenth District.

The Tenth District cited the 2018 U.S. Supreme Court’s Carpenter v. United States decision and found the detective did not need a warrant to request the information from Letgo. The appeals court reasoned the search was lawful because police only obtained a single data point connected to past activity, and it was not an attempt to locate Diaw in real-time, nor was it the location of Diaw’s home.

Diaw appealed to the Supreme Court of Ohio, arguing that under the Carpenter decision, the Fourth Amendment protects individuals in the “whole of their movements, including their physical locations.”

Supreme Court Analyzed Search Warrant Requirement
Chief Justice Kennedy explained that under the Fourth Amendment, law enforcement officers generally need to obtain a search warrant to conduct a search. For most of the nation’s history, Fourth Amendment violation cases typically dealt with the government’s intrusion into a person’s private property, she noted. However, the U.S. Supreme Court also recognized that the Fourth Amendment protects against search of places and items in which a person has exhibited an expectation of privacy, and the expectation is “one that society is prepared to recognize as ‘reasonable.’”

With the development of cases protecting against searches that violated a person’s reasonable expectation of privacy came the third-party doctrine, the opinion noted.

The issue raised in the Carpenter decision was the reasonable expectation one has with information produced by cellphones while they are in use. In Carpenter, the FBI obtained, without a warrant, cell tower location information from two phone service providers. With that information, the FBI tracked the location of a suspect for about 127 days and used the information to examine the suspect’s travel patterns by noting which cell towers his phone “pinged” off.

In Carpenter, the high court noted that the phone produced location information the moment it was turned on, and the suspect argued he did not voluntarily convey the information to the phone companies. The government argued that the suspect signed up for phone service and voluntarily gave his phone information to the companies. The government argued the third-party doctrine allowed the FBI to obtain the information from the phone companies without a warrant.

The U.S. Supreme Court ruled the third-party doctrine does not apply to such a large swath of location information and noted that cellphone use is an “insistent part of daily life.” The opinion stated that location information is involuntarily created because the person’s cellphone generates location information without any action from the user.

Supreme Court Applies Search Requirements to Robbery Suspect
Diaw argued the Carpenter decision applied to his situation and that he did not intend to provide his location data when using his cellphone. He maintained he had a reasonable expectation of privacy in the data stored in his phone, and the police needed a search warrant to access the information.

The chief justice wrote that using a cellphone app is distinctly different from using the phone.

“Start with voluntariness. There is little difficulty concluding that Letgo users voluntarily provide their location information to a third party. Users make the affirmative choice to download Letgo. They also make the choice to create a Letgo account,” the opinion stated.

Unlike the phone itself, the Court found using a marketplace app is not “an insistent part of daily life.” The opinion noted Letgo provided only a single data point that revealed where Diaw had used Letgo, and Diaw had no reasonable expectation of privacy while physically present in a McDonald’s where anyone could see him.

Unlike other cases where Fourth Amendment issues were raised when law enforcement used days’ worth of information to track a suspect, Columbus police received one data point about one past time Diaw used the app, the Court noted.

Further, the Court noted, the purpose of a marketplace app like Letgo is to facilitate local sales through an in-person transaction, which means users are voluntarily alerting others to their general location. The users of Letgo “do not have a reasonable expectation of privacy in that information because they are revealing their location to the public by using the app,” the Court concluded.

The Court remanded the case to the trial court for further proceedings.

2024-1083. State v. Diaw, Slip Opinion No. 2025-Ohio-2323.

View oral argument video of this case.

Please note: Opinion summaries are prepared by the Office of Public Information for the general public and news media. Opinion summaries are not prepared for every opinion, but only for noteworthy cases. Opinion summaries are not to be considered as official headnotes or syllabi of court opinions. The full text of this and other court opinions are available online.