In August 2011 the ACLU issued official records requests to over 380 state and local law enforcement agencies and revealed that virtually all the departments that responded tracked telephones, most without warrants. 

The majority of the two hundred agencies that responded engaged in some cellphone tracking. Only a few those claimed they frequently seek warrants and demonstrate possible cause before tracking mobile phones, according to the ACLU report. 

Most law enforcement agencies claimed they track telephones to research crimes, while others stated that they use tracking only in emergencies like a missing persons case. Only ten agencies said they never use telephone tracking. 

Some law enforcement agencies provided enough paperwork to color an in-depth image of phone tracking activities. For instance, Raleigh, North Carolina, tracks hundreds of telephones a year primarily based on invoices from telephone companies. In Wilson County, North Carolina, police get historic tracking information where it's "relevant and material" to a continuing inquiry, a standard the ACLU notes is lower than possible cause. 

Police in Lincoln, Nebraska, obtain GPS location information on phones without demonstrating probable cause. GPS location information is even more definite than cell tower location information, according to the ACLU. 

Similarly, the ACLU points out that cellphone tracking has become so common that phone companies have manuals that explain to police what data the firms store, how much they charge for access to information and what's required for police to access it. 

But some law enforcement agencies do seek warrants and probable cause before tracking mobile phones. Police in the County of Hawaii, Hawaii, Wichita, Kansas and Lexington, Kentucky, do seek 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 wants, then surely other agencies can as well." 

Tags: ACLU, GPS, Warrant-less search