(CNN) — The Supreme Court on Monday ruled that the use of a “geofence warrant” to capture location data from cell phones in search of a robbery suspect constituted a search for Fourth Amendment purposes, a decision that means officers will have to obtain a warrant to access such data in the future. Justice Elena Kagan wrote the opinion for a majority that included both conservative and liberal justices. The court divided 6-3, with three of the court’s conservatives dissenting.