Cellphone towers are one tool police agencies may try to use to collect data from your mobile phone.Christian Delbert/Shutterstock

The Center for Investigative Reporting has recently told you about how local law enforcement agencies in California are using emerging technology – such as license-plate scanners and facial recognition software – to collect citizens’ data in new ways. But did you know the extent to which police can tap directly into information about your cellphone?

A new investigation by USA Today and Gannett offers a window into the new technologies and tactics police are using to bulk collect cellphone data. Their reporting reveals how many law enforcement agencies use a device that impersonates a cellphone tower – called a Stingray – to capture location and activity information from cellphones in the area.

Of 125 police agencies in 33 states that were reviewed by USA Today and Gannett, at least 25 own a Stingray. Most of the devices were purchased through federal antiterrorism grants, which have helped fund an array of high-tech, combat-ready gear for state and local police.

One in four police agencies analyzed also have used a tactic called a “tower dump” to obtain data on the identity, activity and location of any phone that connects to an individual cellphone tower over a set timespan. While police say the data can assist in solving and preventing crimes, USA Today also highlights a few cases in which data collection has been abused. In Minnesota, for example, state auditors found that 88 police officers across the state improperly looked up Minnesotans’ driver’s license information without authorization or relevance to an investigation last year.

As part of Gannett’s investigation, The Desert Sun surveyed how Southern California law enforcement agencies have collected cellphone data. See the infographic on its website for a breakdown of how the technology works.

What are the legal implications for bulk collection of cellphone data? As USA Today points out, they’re fuzzy, and privacy advocates have questioned the legal standards. Last year, CIR reporter G.W. Schulz highlighted a court brief filed by the Electronic Frontier Foundation and American Civil Liberties Union of Northern California that argued that Stingrays are “highly intrusive and indiscriminate.” 

But as the technology is deployed, states are responding in different ways. Montana and Maine passed laws requiring police to show probable cause and get a search warrant to obtain some cellphone data this year, while California Gov. Jerry Brown vetoed a similar measure last year. See ProPublica’s overview of data collection laws for a look at state-level developments.

USA Today’s investigation comes on the heels of new revelations that the National Security Agency is gathering nearly 5 billion cellphone location records a day, as reported by The Washington Post.

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Cole Goins is the director of community engagement for Reveal, where he cultivates partnerships that blend in-depth journalism and creative public engagement. He has built and supported distribution networks, spearheaded arts-based initiatives such as the Off/Page Project, led social media and audience strategy, and facilitated statewide media collaborations. He was a senior fellow in the 2015 USC Annenberg Health Journalism Fellowships, mentoring five journalists on approaches to community engagement. Previously, Goins was the engagement editor at the Center for Public Integrity, where he led audience development initiatives and multimedia features for award-winning investigative projects. He earned a degree in journalism from the University of North Carolina at Chapel Hill, where he worked as music director for WXYC, the student-run radio station. He is based in Reveal's Emeryville, California, office.