Map of ACLU Affiliates that filed FOI requests (photo: ACLU )


Public records from local and state law enforcement agencies reveal a significant number of law enforcement agencies in the United States use cell phone tracking even if they do not have a warrant or probable cause to engage in such surveillance. The American Civil Liberties Union (ACLU), which requested and obtained the records, finds the records are troubling as they show law enforcement is using different rules or sometimes no rules when using location tracking to fight crime.


The findings come from “5,500 pages of documents from over 200 local law enforcement agencies regarding cell phone tracking.” The documents were part of a request made in August 2011 by 35 ACLU affiliates for information on policies, procedures and practices that law enforcement agencies use to track cell phones.

The details were the subject of a major New York Times article published over the weekend by Eric Lichtblau. David Dayen covered the widespread use of cell phone tracking this morning in a brief post. Now, the ACLU has posted material that provides more explicit details on law enforcement use of location tracking. (Note: The records do not involve law enforcement use of wiretaps.)


The ACLU makes it clear that legal standards could be followed but many agencies do not follow such standards. While the “County of Hawaii,Wichita, and Lexington, Ky. demonstrate probable cause and obtain a warrant when tracking cell phones,” most other police departments do not. In fact, the records show police in Lincoln, Nebraska, obtain GPS location data without probable cause and police in Wilson County, North Carolina, use “historical cell tracking data” when it is “relevant and material.”

Catherine Crump, a staff attorney with the ACLU, explains, “Relevance is a really low standard.” This is why what the Wilson County Police Department is doing is problematic and why law enforcement should be required to have probable cause.

“Virtually anything can be relevant,” Crump notes. “When law enforcement agents say they have probable cause, it means they have a good reason to believe that a search will turn up evidence of wrongdoing.” Additionally, Crump finds law enforcement should get ”a judge to agree with them that they have probable cause because a judge is a neutral party” and less violations of privacy are likely to occur.


The findings show law enforcement make a distinction between needing the contents of communication and information that communication happened when engaging in location tracking. If content isn’t needed, law enforcement believes they do not necessarily need a warrant. For example, the Delaware Department of Justice will use an “Attorney General’s subpoena” if they do not need the “content of communications.” This distinction is often made, according to Crump.

“Obviously, when law enforcement looks at the content of the communication, that’s very sensitive because people express their thoughts,” states Crump. “Law enforcement shouldn’t be getting that without a warrant based on probable cause. But other types of information can be sensitive too.”

She outlines:

I think location information can be sensitive. Knowing where someone goes can reveal a great deal about who they are. And the Supreme Court has recognized that location information can be very sensitive. In US v. Jones, the Court held that it is a search under the Fourth Amendment when law enforcement agents attach a GPS device to someone’s car and track people’s movements. And if it is a search to track the movements of  someone’s car, then surely tracking someone’s cell phone, which goes with them wherever they go all day long, is also deserving of Fourth Amendment protection.

The records show that law enforcement agencies sometimes “track every telephone that called or was called by a specific phone.” In Chatham County, NC, law enforcement requested “GPS and other information relevant to [the target number] and other telephones of whatever type with which [target number] communicates.” Agents are also collecting ”cell phone numbers of all individuals located at a particular location at a particular time.” For example, in Tucson, Arizona, T-Mobile charged $150 for an hour of data from phones near a particular tower. Verizon Wireless charged $30-$60 for 15 minutes of tower data. (This is called a “tower dump.”)

At least one agency that uses location tracking is aware that the practice can be unsettling to the public. Crump told MSNBC, “An Iowa City police training manual instructs officers, ‘Do not mention to the public or the media the use of cellphone technology or equipment used to locate the targeted subject,’ and also advises officers to keep that information out of police reports.”


Law enforcement agencies rely on cell phone companies for location data. Companies hold on to data for a “very long time,” a fact that is not disclosed in the privacy policies of these companies. Verizon, according to the Justice Department, “keeps location records for ’1 rolling year.’ T-Mobile keeps them for ‘officially 4-6 months, but really a year or more.’ Sprint keeps these records for 18-24 months. AT&T retains location data “since July 2008.”

Most law enforcement agencies rely on cell phone carriers to obtain information but a few law enforcement agencies are able to purchase their own cell tracking technology. Using grant money from the Homeland Security Department, the Gilbert Police Department in Arizona purchased cell phone tracking equipment in June 2008 for $244,195.


Cell phone companies make a lot of money off requests for data. The ACLU also reports that, in some instances, companies are providing legal guidance on location tracking to law enforcement.

Back in August, I spoke with Crump on the Freedom of Information Act requests being filed by affiliates to obtain the records. She said that she believed the records would show “technology tracking” was being used more and more often. She thought this would be the case because the old model of law enforcement, where one person is tracked, was becoming obsolete.


Today, Crump concludes, “Technology has evolved very rapidly and the law hasn’t kept pace.” To address this problem, the ACLU would like to see Congress and state legislatures “adopt legislation to make clear that law enforcement agents can’t track the location of cell phones without a warrant for probable cause.”

Location tracking has developed into an incredibly potent issue. Last year, it was reported that Sen. Ron Wyden (D-OR) knew the NSA was seriously compromising Americans’ privacy through location tracking. Matt Olsen, who had just moved from the National Security Agency (NSA) to become the head of the National Counterterrorism Center (NCTC), was asked during his confirmation hearing if the NSA was using cell phone data to track Americans. Olsen said there are “circumstances where that authority may exist.” Sen. Wyden and Sen. Mark Udall (D-CO) wanted to publicize details on this “authority.”


Outside of this effort by Sens. Wyden and Udall, there has not been much congressional action on location tracking. However, as Crump mentioned, the Supreme Court did reaffirm the Fourth Amendment rights of Americans in a January decision involving a case where law enforcement unconstitutionally used GPS tracking.

It was a major victory for privacy and, if Congress and state legislatures do not pass legislation to address the evolution of technology, perhaps, a string of court decisions from lower courts will eventually help rein in warrantless location tracking by law enforcement.