Securus Technologies’ programs are used in thousands of prisons and detention centers nationwide to track calls to inmates, but the company’s offerings are also capable of tracking and geolocating people’s cellphones without any warrant or oversight, The New York Times reports. Securus obtains location information though data from major cellphone providers the same way marketers do. It also advertises the technology to law-enforcement agencies as a tool to find murder suspects, missing people, and those at-large—but the feature can easily be abused for access to millions of cellphone users. One Missouri sheriff used the service at least 11 times between 2014 and 2017, and secretly tracked state highway patrol members and a judge, prosecutors said. While the company said it “required customers to upload a legal document” to certify the location lookup, the Federal Communications Commission claims Securus did not “conduct any review of surveillance requests”—giving law enforcement tracking power without verification of approval or oversight.