Police are spending millions of dollars to monitor the social media of protesters and suspects

Hundreds of local police departments across the United States have collectively spent about $4.75 million on software tools that can monitor the locations of activists at protests or social media hashtags used by suspects, according to new research. The research, by the Brennan Center for Justice, a nonprofit organization focusing on criminal justice issues, aims to take a comprehensive look at the fast-growing phenomenon of social media-monitoring by law enforcement. Using public records, the Brennan Center tracked spending by 151 local law enforcement agencies that have contracted with start-ups that siphon data from Facebook, Instagram, Twitter and other sites, largely out of the public eye. Top spenders were the City of Los Angeles, the Texas Department of Public Safety, the County of Sacramento, the Florida Department of Law Enforcement and the County of Macomb, which is a large county in Michigan. Each spent roughly $70,000 over the past three years, Brennan found.