US appeals court: cell phone search is unconstitutional

Police searches using location data from random cell phones are unconstitutional, the US Court of Appeals for the Fifth Circuit has unanimously ruled. This type of dragnet search is a violation of the Fourth Amendment of the US Constitution, which prohibits arbitrary searches. Civil rights activists such as the Electronic Frontier Foundation (EFF) welcome the ruling, with which the court deliberately opposes the Fourth Circuit. There, the so-called geofence warrants are deemed permissible.

The reason for the current decision [i]United States v Smith et al[/i] (case no. 23-60321) is a raid on a US Postal Service truck in Mississippi in February 2018. In November 2018, the postal police used the then relatively new method of obtaining a warrant against Google. The data company was then required to disclose which Android phones with location history enabled had been in an area of around 100,000 square meters around the crime scene during a certain hour on the day of the attack. Location history is not activated in Android's default settings.

Google has to search through the location histories of all Android users worldwide. Because the company receives tens of thousands of such commands every year, this takes a few months. In addition, it is not always possible to narrow down the location exactly. Hits are then sifted and enriched with data from mobile network operators and other sources. In April 2019, Google provided identification numbers of three Android devices that were located in an area of around 328,000 square meters at the time in question (one using GPS, two using Wi-Fi data). Two of these eventually led the investigators to two men; one of them was subsequently identified by a witness. Both suspects were eventually convicted of the robbery along with a third man.

Unconstitutional, but no ban on evidence in the specific case

They challenged this ruling by arguing that the search of the location history of all Android accounts was a violation of the Fourth Amendment of the US Constitution, which is why the evidence obtained from it should not have been used in the trial. The Federal Court of Appeal now partially agrees with them: Android users can assume that their location data history will remain secret. The Fourth Amendment of the US Constitution is fundamentally designed to protect against government fishing expeditions in the form of unrestricted searches (general warrants). Therefore, search warrants directed at virtually anyone's location data are "categorically excluded".

However, the postal police had acted in good faith in the legality of their actions at the time, which is why the use of the evidence was permissible. The conviction of the three men therefore remains in place. However, future investigations in Louisiana, Mississippi and Texas will no longer be allowed to use this variant of dragnet searches with queries of the location history of all Android cell phones – unless the US Supreme Court decides otherwise.

Different opinion: Fourth Circuit

It is not at all unlikely that the Supreme Court will deal with the matter in this or another case. In July, the US Court of Appeals for the Fourth Circuit ruled 2:1 that the location tracking of all Android phones for a two-hour period was not an invasion of privacy at all(United States v. Chatrie, Case No. 22-4489). This means that not even a judicial search warrant is required. Chatrie has petitioned for reconsideration by an expanded bench of the same court, but there is no legal right to do so. The Fourth Circuit includes Maryland, North and South Carolina, Virginia and West Virginia.

Thus, there are two diametrically opposed decisions from federal appellate courts, which greatly increases the likelihood of an argument before the US Supreme Court (SCOTUS). Moreover, in recent years, the SCOTUS has overturned a particularly large number of decisions from the Fifth Circuit, whose court is considered the most conservative in the country. At the same time, the decision from the Fourth Circuit may contradict an earlier SCOTUS ruling: In Carpenter v United States, the high court recognized that investigators may only obtain cell phone location data from mobile network providers through a warrant. In order to obtain a warrant, law enforcement must already have other information that gives rise to a concrete suspicion of a crime. Accordingly, US courts should not issue a search warrant to monitor any cell phone whose owner has no concrete suspicion.

The case of State v Contreras-Sanchez (Case No. A22-1579) is currently pending before the Supreme Court of the US state of Minnesota. There, the investigators wanted to know from Google which Android phones had driven along a certain road – during an entire month. Google eventually handed over the data for one week. The EFF is a party to the lawsuit and argues that the comprehensive data analysis of all Android phones worldwide is a violation of the Minnesota Constitution and the Fourth Amendment of the US Constitution. The recent decision by the Fifth Circuit could help.

• USA v SMith et al Fifth Circuit
• USA v Chatrie , fourth circuit

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