The US Court of Appeals for the Fourth Circuit [official website] ruled [opinion, PDF] Wednesday that US border authorities may not search detainees’ cell phones and other electronic devices without individualized suspicion of wrongdoing.

After apprehending Turkish citizen Hamza Kolsuz at the Washington Dulles International Airport in 2016, authorities conducted an extensive data extraction process that lasted one month and yielded an almost 900-page report including personal contacts, emails, and a history of GPS coordinates.

Kolsuz filed a motion to suppress the report, which was denied by the district court, claiming the search violated his Fourth Amendment rights.

Although affirming the denial of the motion, the court found that “forensic searches of digital phones must be treated as a non-routine border search, requiring some form of individualized suspicion.”

While recognizing the importance of protecting from arbitrary invasions into personal information of detainees, the court explicitly declined to decide whether a higher standard of probable cause or a warrant is required.