https://techcrunch.com/2022/07/18/homeland-security-cell-phone-tracking/

The Department of Homeland Security (DHS) used mobile location data to track people’s movements on a much larger scale than previously known, according to new documents unearthed by the American Civil Liberties Union (ACLU).

It’s no secret that U.S. government agencies have been obtaining and using location data collected by Americans’ smartphones. In early 2020, a Wall Street Journal report revealed that both Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP) bought access to millions of smartphone users’ location data to track undocumented immigrants and suspected tax dodgers.