SAN FRANCISCO – U.S. police departments used location data and other user information from Twitter, Facebook and Instagram to track protesters in Ferguson, Missouri, and Baltimore, according to a report from the American Civil Liberties Union on Tuesday. Facebook, which also owns Instagram, and Twitter shut off the data access of Geofeedia, the Chicago-based data vendor that provided data to police, in response to the ACLU findings. The report comes amid growing concerns among consumers and regulators about how online data is being used and how closely tech companies are cooperating with the government on surveillance. "These special data deals were allowing the police to sneak in through a side door and use these powerful platforms to track protesters," said Nicole Ozer, the ACLU's technology and civil liberties policy director. The ACLU report found that as recently as July, Geofeedia touted its social media monitoring product as a tool to monitor protests.