As you may recall, we blogged about a Seventh Circuit Stingray (cell-site simulator or CSS) case here last year. In United States v. Patrick, the Seventh Circuit expressed interest in but did not reach the question whether the use of a Stingray implicates the Fourth Amendment. This question has become even more interesting since the Supreme Court's cert grant in Carpenter v. United States (Question presented: "Whether the warrantless seizure and search of historical cell-phone records revealing the location and movements of a cell-phone user over the course of 127 days is permitted by the Fourth Amendment").
Now entering the fray: a suppression motion in United States v. Ellis, being litigated by a former federal prosecutor. Issues include whether the government's warrantless use of a Stingray is a "search" for Fourth Amendment purposes; whether Franks requires government agents to disclose their reliance on Stingrays in search-warrant affidavits; and whether the warrantless use of a Stingray can be excused if the officers acted in "good faith." Here is the government's opposition to the motion. The hearing is scheduled for August 2. Stay tuned.