In August 2011 the ACLU issued public documentation requests to over 380 state and local law enforcement agencies and found that almost all the departments that replied tracked cellphones, most without warrants. 

The great majority of the 2 hundred agencies that replied engaged in some cellphone tracking. Only a few those claimed they regularly seek warrants and demonstrate probable cause before tracking mobile phones, according to the ACLU report. 

Most law enforcement agencies said they track telephones to analyze crimes, while others claimed they use tracking only in emergencies like a missing people case. Only 10 agencies stated that they never use mobile phone tracking. 

Some law enforcement agencies provided enough paperwork to color a meticulous image of cellphone tracking activities. For example, Raleigh, North Carolina, tracks masses of telephones per year based on invoices from telephone firms. In Wilson County, North Carolina, police get historical tracking data where it's "relevant and material" to an ongoing inquiry, a standard the ACLU notes is lower than possible cause. 

Police in Lincoln, Nebraska, get GPS location information on telephones without demonstrating probable cause. GPS location info is far more precise than cell tower location info, according to the ACLU. 

Furthermore, the ACLU observes that cellphone tracking has gotten so common that mobile phone corporations have manuals that explain to police what data the corporations store, how much they bill for access to data and what's required for police to access it. 

However , some law enforcement agencies do seek warrants and likely cause before tracking cellphones. Police in the County of Hawaii, Hawaii, Wichita, Kansas and Lexington, Kentucky, do search for a warrant and possible cause. 

The ACLU claims that if "police departments can protect both public safety and privacy by meeting the warrant and probable cause requirements, then certainly other agencies can as well." 

Tags: ACLU, GPS, Warrant-less search