The American Civil Liberties Union of Connecticut Wednesday filed requests with the Connecticut State Police and six city police departments - including New London's - for information on how they use cellphone tracking data in their investigations.

The Freedom of Information requests are part of a nationwide campaign by the ACLU to uncover possible abuses of that power by law enforcement agencies.

The ACLU argues that obtaining cellphone location data without a warrant or showing probable cause constitutes a violation of Americans' Fourth Amendment protection from unreasonable search and seizure.

The six cities served with FOI requests are Waterbury, Danbury, Willimantic, New Haven, New London and Berlin.

Asked why these cities, and particularly New London, were targeted, Connecticut ACLU staff attorney David McGuire said that - except in the case of Berlin - it was purely to get a good geographical sample of what different departments were doing around the state.

"We picked New London because it's arguably the biggest city in the southeastern part of the state, and each city has its own police culture," McGuire said. "It's not like we dislike New London. We just wanted to get a sense of how this technology is being used and how large this problem is."

Asked about the New London department's use of cellphone tracking, Police Chief Margaret Ackley said in an email Wednesday night that "tracking the exact location of a live cellphone is only done for exigent circumstances, such as in an abduction case. They are referred to as a 'ping' and are done through the cell phone carrier."

"They are rather infrequent," Ackley said. "New London spends zero dollars tracking live cellphones."

In Berlin, federal investigators collected information without warrants on calls to and from 180 mobile phone numbers as well as their locations in an effort to track down conspirators in a 2008 bank robbery.

While Luis and Felix Soto robbed a Webster Bank there, accomplices used their cellphones to make 911 calls to Berlin police to draw them to a phony home invasion several miles away.

Without seeking a warrant, police obtained cellphone tower locations for all incoming and outgoing calls from 180 different phone numbers to track down the other participants in the robbery.

The ACLU filed an amicus brief in that case, arguing that the evidence obtained from the cellphones be suppressed because it was obtained without a warrant and demonstration of probable cause.

"The Fourth Amendment requires the government obtain a warrant based on probable cause and particular description to access cell site location information," the ACLU argued in its brief. "This is because location tracking using cell site location information is a 'search' under the Fourth Amendment that infringes on the reasonable expectation of privacy that Americans have traditionally enjoyed in their whereabouts."

The broader problem now, in the view of the ACLU, is that police departments can seek a warrant to acquire a person's cellphone location data simply on the pretext that it may be "relevant to the case," McGuire said. "And anything can be 'relevant.' They don't have to show probable cause," he added.

Officers can then "show your cellphone provider a court order," he said, "and the provider will give them the records to show where you are at any particular time."

And, as these warrants are obtained under seal, the suspect will have no way of knowing he or she is being monitored.

This is one example, McGuire said, of how Americans' rights to privacy are being threatened by technological advances.

"There are all these areas where technology has gotten ahead of the law," he said, "and we're very concerned about encroachments on privacy."

Nationally, the ACLU is seeking the following information from law enforcement agencies: whether the agencies demonstrate probable cause and obtain a warrant to access cellphone location data, statistics showing how frequently the agencies obtain the data and how much money they spend to obtain it.

"The ability to access cellphone location data is an incredibly powerful tool and its use is shrouded in secrecy," said Catherine Crump, staff attorney for the national ACLU's Speech, Privacy and Technology Project. "The public has a right to know how and under what circumstances their location information is being accessed by the government."

k.robinson@theday.com