The "stingray" is a surveillance device that mimics a cell tower and can be used to track a person's location or access data on their cellular device. Several California police agencies are utilizing the technology, but how they obtained it or what they are using it for is, at best, shadowy.
[Some agencies] have used its stingray(s) for ordinary law enforcement purposes, such as investigating guns, drugs, and gangs. While these are legitimate law enforcement purposes, they don't justify suspending the Fourth Amendment or bypassing ordinary democratic processes.
How the departments acquired the technology is uncertain, and the ACLU says there is scant evidence in the heavily redacted invoices provided by law enforcement.
The [Oakland Police Department] unit that used the stingray, the Criminal Investigation Division, focuses its investigative resources on guns, drugs, and gangs. OPD produced a lone invoice pertaining to the stingray - " $13,425 spent in 2009 for "Maintenance Services." How it acquired the device remains a mystery.
The report sees the legal grey area around stingrays as part of a larger "disturbing trend" and urge official regulations for the use of such powerful tools, saying that "as with too many other surveillance devices, law enforcement is writing its own guidelines."
The following agencies already have stingray technology or have applied for grant funding to purchase it:
Via ACLU/Free Future