NEW YORK -- According to data released by the New York Civil Liberties Union, the New York Police Department has used secretive cellphone tracking technology more than 1,000 times since 2008.
A cell-site simulator can sweep up basic cellphone data by tricking phones in the area to believe that it's a cell tower, allowing it to identify unique subscriber numbers. The data are then transmitted to police, helping them determine the location of a phone without the user making a call or sending a text message.
Federal guidelines adopted in September require a warrant be routinely obtained to use the technology. The rules don't apply to local law enforcement.
The NYPD says it had no written policy for its use.
Police records show the technology helped catch suspects in kidnappings, rapes and murders.