From Juliet Bennett Rylah's 8-18-15 LAist.com article entitled "How the LAPD Has Been Hacking Our Phones For Years":
LAPD has had access to a device called a "dirtbox" for the past several
years. This equipment allows them to intercept calls and text messages
from numerous cellphones at once.
"dirtbox" gets its name from the acronym of the company that makes
them: Digital Receiver Technology, Inc., which is owned by The Boeing
Co. These devices, which used by the military and the Justice
Department, are also being used by police. Police departments in both
Chicago and L.A. bought the equipment in 2005, according toan investigation by Reveal News.
Los Angeles spent $260,000 on the equipment, using money from a
homeland security grant to pay for the actual devices and a two-week
training program on how to use it. Their reasoning was the same as it
always is:to fight terrorism. Chicago, on the other hand, used funds from the controversial practice ofasset forfeiture.
dirtbox is something called a cell site simulator, and it works by
mimicking a cell phone tower. Cell phones within range start using the
dirtbox, and any information—voice calls, who you've called, texts, data
you've sent—is intercepted and decrypted as it passes through. A
dirtbox is capable of drawing from 200 cellphones at a time, and it can
also jam signals....