The NYPD is reportedly putting together a database of cell phone users-- logging serial numbers from suspects' phones to try to connect them to past or future crime.
A recent internal memo says that when cops make an arrest, they should remove the suspect's cell phone battery and then log the International Mobile Equipment Identity number, which is unique to each phone, the Daily News reported.
With the availability of disposable cell phones that can be bought with cash or operated with phone cards, the file could be extremely useful to investigating drug rings and other criminal enterprises, police sources say.
"It's used to help build cases," one source said of the new initiative.
But the amassing of data has some skeptics. New York Civil Liberties Union associate legal director Christopher Dunn told the Daily News it appears the NYPD is "taking phones apart to get information" without warrants.
There are limits to the data's usefulness - all Chinese-made cells sold in India have the same number and some overseas cells are embedded with fake numbers.